Magnetic effect of electric current and light
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Question 1 |
The space surrounding a magnet where a magnetic force is experienced is called _______
magnetic field | |
magnetic lines of force | |
magnetic poles | |
magnetic induction |
Question 2 |
The path taken by the north pole is called _________
magnetic force | |
magnetic field | |
magnetic lines of force | |
magnetic intensity |
Question 3 |
The characteristics of magnetic lines of forces is ________
field lines emerges from north pole and merge at south pole | |
closed curves | |
never cross each other | |
all the above |
Question 4 |
When current flows in a wire, it creates_______
an electric field outside | |
magnetic field around it | |
both the electric and magnetic fields | |
neither the electric nor the magnetic fields |
Question 5 |
What is the direction of magnetic needle placed near the conductor in which current flows in clockwise direction?
move towards east | |
move towards west | |
No movement | |
Move opposite i.e. south to north |
Question 6 |
which of the following correctly describes the magnetic field near a long straight wire?
The field consists of straight lines perpendicular to the wire | |
The field consists of straight lines parallel to the wire | |
The field consists of radial lines originating from the wire | |
The field consists of concentric circles centred on the wire |
Question 7 |
The direction of magnetic field around a straight conductor carrying current can be determined by ________
Fleming’s right hand rule | |
Fleming’s left hand rule | |
Lenz’s law | |
None of the above |
Question 8 |
Magnetic field is produced by the flow of current in a straight wire. This phenomenon was discovered by ________
Maxwell | |
Faraday | |
Oersted | |
Coulomb |
Question 9 |
The magnetic lines of force, inside a current carrying circular loop are_______
circular at the ends but they are parallel to the axis inside the loop | |
along the axis are parallel to each other | |
perpendicular to the axis and equidistance from each other | |
concentric circles |
Question 10 |
What is the direction of magnetic field at the centre of a coil carrying current in anticlockwise direction?
along the axis of the coil inwards | |
along the axis of the coil emerges outwards | |
perpendicular to the axis of the coil inwards | |
perpendicular to the axis of the coil outwards |
Question 11 |
The strength of the magnetic field due to a current carrying conductor depends on _________
number of turns of a coil | |
magnitude of current | |
size of the coil | |
all the above |
Question 12 |
The magnetic field produced due to a circular wire at its centre is _____
in the plane of the wire | |
perpendicular to the plane of the wire | |
at 450 to the plane of the wire | |
none of the above |
Question 13 |
A current carrying conductor placed in a magnetic field experiences_______
mechanical force | |
magnetic force | |
electrical force | |
gravitational force |
Question 14 |
A current carrying conductor experiences a force in a magnetic field was shown by _________
Hans Christian Oersted | |
Michael Faraday | |
Andre Marie Ampere | |
Fleming |
Question 15 |
Name the effect of current when a current carrying conductor is placed in a magnetic field______
electrical effect | |
mechanical effect | |
magnetic effect | |
heating effect |
Question 16 |
The direction of mechanical force produced by a current carrying conductor in a magnetic field is __________
perpendicular to the direction of magnetic field only | |
perpendicular to the direction of current flow | |
perpendicular to both the direction of current and magnetic field | |
parallel to the direction of magnetic field |
Question 17 |
The direction of force on the current carrying conductor depends upon______
direction of current | |
direction of magnetic field | |
direction of suspension of a conductor | |
direction of current and direction of magnetic field |
Question 18 |
The magnitude of mechanical force acting on a current carrying conductor in proportional to _________
current | |
magnetic induction | |
length of the conductor | |
all the above |
Question 19 |
The force of a conductor is maximum when the current carrying conductor is _______
along the magnetic field | |
at right angles to the magnetic field | |
towards east | |
towards west |
Question 20 |
When the current carrying conductor is placed along the direction of magnetic field, then the force is ________
maximum | |
minimum | |
zero | |
equal to one |
Question 21 |
When a current carrying conductor is placed in a strong magnetic field, the direction of force is determined by __________
Right hand thumb rule | |
Fleming’s left hand rule | |
Fleming’s right hand rule | |
Faraday’s law |
Question 22 |
In Fleming’s left hand rule, the first three fingers of the left hand are stretched at _______
acute angles | |
obtuse angles | |
right angles | |
none |
Question 23 |
The motion of the conductor in Fleming’s left hand rule is represented by ________
fore finger | |
thumb | |
middle finger | |
none |
Question 24 |
In Fleming’s left hand rule, the forefinger represents the direction of_________
magnetic field | |
current | |
motion of a conductor | |
electric field |
Question 25 |
The direction of current in Fleming’s left hand rule is represented by ______
thumb | |
forefinger | |
middle finger | |
little finger |
Question 26 |
An electric motor converts________
mechanical energy into electrical energy | |
mechanical energy into heat energy | |
electrical energy into heat energy | |
electrical energy into mechanical energy |
Question 27 |
The coil used in a DC motor is called ______
split ring | |
armature | |
resistance coil | |
induction coil |
Question 28 |
In DC motor, the split rings are known as ________
slip rings | |
armature | |
commutator | |
resistor |
Question 29 |
An electric motor uses __________ to reverse current.
transformer | |
sliprings | |
commutator | |
brushes |
Question 30 |
The direction of force in DC motor is given by __________
Fleming’s left hand rule | |
Fleming’s right hand rule | |
Right hand thumb rule | |
Lenz law |
Question 31 |
In DC motor, the two equal and opposite forces constitutes________
torque | |
magnetic induction | |
couple | |
restoring |
Question 32 |
. In DC motor, the couple rotates the coil in the _______
clockwise direction | |
upward direction | |
anticlockwise direction | |
downward direction |
Question 33 |
The coil in electric motor continues to rotate in the anticlockwise direction as long as____
existence of magnetic field | |
current in the coil is zero | |
at restoring force in the coil | |
current flows through it |
Question 34 |
The couple in an electric motor is to ____
vibrate the coil | |
stop the coil | |
rotate the coil | |
oscillate the coil |
Question 35 |
The power of an electric motor can be increased by ______
increasing the number of turns in armature | |
decreasing the number of turns in the coil | |
decreasing the current | |
decreasing the strength of the magnetic field |
Question 36 |
In an electric motor when the current is increased, ________
energy is increased | |
power is decreased | |
power is increased | |
energy is decreased |
Question 37 |
The total number of magnetic lines of forces crossing a given area is _______
magnetic field | |
magnetic induction | |
magnetic strength | |
magnetic flux |
Question 38 |
The commercial motors use______
electro magnet | |
permanent magnet | |
horse shoe magnet | |
bar magnet |
Question 39 |
The phenomenon of electromagnetic induction was discovered by _______
Ampere | |
Christian Oersted | |
Lenz | |
Michael Faraday |
Question 40 |
Electromagnetic induction is involved in _______
rotation of the coil of an electric motor | |
charging a body with negative | |
production of current by relative motion between a magnetic and a coil | |
generation of magnetic field due to a current carrying loops |
Question 41 |
The generation of emf by varying the magnetic field is ______
electrostatic induction | |
magnetic induction | |
electromagnetic induction | |
mechanical effect of current |
Question 42 |
In Faraday’s experiments, there is a deflection in the galvanometer when a ______
magnet is moved towards the coil | |
coil is moved towards the magnet | |
by changing the magnitude of current | |
all the above |
Question 43 |
The current due to the relative motion between the coil and the magnet is called_________
direct current | |
alternating current | |
induced current | |
none of these |
Question 44 |
The phenomenon of inducing an emf, when the magnetic flux linked with a coil, changes is called______
electromagnetic induction | |
electric induction | |
electrostatic induction | |
magnetic induction |
Question 45 |
The induced emf depends on ______
magnetic induction | |
number of turns of the coil | |
relative speed between the magnet and the coil | |
all the above |
Question 46 |
The induced emf is independent on __________
magnetic induction | |
number of turns of the coil | |
relative speed between the magnet and the coil | |
length of the magnet |
Question 47 |
Who stated that whenever there is a change in the magnetic flux linked with a coil an emf is induced in it?
Faraday’s law | |
Newton’s law | |
Fleming’s left hand rule | |
generator rule |
Question 48 |
The direction of induced current is given by ______
Ampere rule | |
Fleming’s left hand rule | |
Fleming’s right hand rule | |
Thumb rule |
Question 49 |
When a current carrying conductor is placed in a strong magnetic field, the direction of force is determined by ________
Fleming’s left hand rule | |
Faraday’s law | |
Fleming’s right hand rule | |
Right hand thumb rule |
Question 50 |
Fleming’s right hand rule is also known as ___________
motor rule | |
cork screw rule | |
thumb rule | |
generator rule |
Question 51 |
In Fleming’s right hand rule, the thumb represents________
direction of magnetic field | |
direction of induced current | |
direction of force | |
motion of conductor |
Question 52 |
The middle finger in the Fleming’s right hand rule represents _________
direction of induced current | |
direction of magnetic field | |
direction of force | |
motion of conductor |
Question 53 |
Which phenomenon is used to produce large currents?
Magnetic induction | |
Electrostatic induction | |
Electromagnetic induction | |
Friction |
Question 54 |
Generator is used to convert______
mechanical into electrical energy | |
electrical into mechanical energy | |
electrical into sound energy | |
sound into electrical energy |
Question 55 |
AC generator works on the principle of ________
photo electric effect | |
mechanical effect of current | |
electrostatic induction | |
electromagnetic induction |
Question 56 |
In an Ac generator, the direction of the induced emf at any instant is given by ______
Fleming’s right hand rule | |
Fleming’s left hand rule | |
Cork screw rule | |
Right hand thumb rule |
Question 57 |
The field magnet used in AC generator is ______
an electromagnet | |
horse shoe magnet | |
bar magnet | |
powerful permanent magnet |
Question 58 |
In generator, the armature is rotated about its axis______
parallel to the magnetic field | |
parallel to the direction of induced emf | |
perpendicular to the direction of magnetic field | |
perpendicular to the direction of induced emf |
Question 59 |
The two ends of the coil in AC generator is connected to ________
brushes | |
slip rings | |
split rings | |
axle |
Question 60 |
When the coil is rotated about an axis perpendicular to the direction of magnetic field in AC generator, there is a continuous change in the ________
induced current | |
induced emf | |
magnetic pole strength | |
magnetic flux |
Question 61 |
In generator, the change in the magnetic flux linked with the coil induces_______
charges | |
current | |
an emf | |
electric field |
Question 62 |
The direction of induced current at any instant in generator is given by _______
cork screw rule | |
ampere’s rule | |
Fleming’s right hand rule | |
Fleming’s left hand rule |
Question 63 |
In AC generator, the emf varies for every_______
full rotation of the coil | |
half rotation of the coil | |
one fourth rotation of the coil | |
three fourth rotation of the coil |
Question 64 |
A current which changes direction after equal intervals of time is _____
direct current | |
eddy current | |
alternating current | |
steady current |
Question 65 |
The principle used in DC generator is ________
mechanical effect of current | |
electromagnetic induction | |
electrostatic induction | |
Ampere’s law |
Question 66 |
DC generator is used to generate ______
steady current | |
eddy current | |
unidirectional current | |
alternating current |
Question 67 |
The ends of the coil in DC generator is connected to ________
split rings | |
slip rings | |
brushes | |
axle |
Question 68 |
The rectangular coil of many turns wound on a soft iron core is called _______
split rings | |
carbon brushes | |
armature | |
slip rings |
Question 69 |
The split rings in a DC generator is used to ______
increase the current | |
decrease the current | |
reverse the current | |
invert the current |
Question 70 |
Which part is used to convert AC into DC?
slip rings | |
carbon brushes | |
coil | |
split rings |
Question 71 |
. The induced current from the generator is passed to the external circuit through ________
split rings | |
armature | |
commutator | |
carbon brushes |
Question 72 |
In an AC generator, the emf obtained can be increased by ________
increasing the numbers of turns of the coil | |
increase the speed of rotation of the coil | |
using a strong field magnet | |
all the above |
Question 73 |
Alternating current changes its direction ________
uniformly | |
periodically | |
instantaneously | |
spontaneous |
Question 74 |
Mirrors having a spherical surface of reflection are ______
plane mirrors | |
lenses | |
spherical mirrors | |
prism |
Question 75 |
A spherical mirror, which has reflecting curved inward surface is _________
concave mirror | |
convex | |
Plano concave | |
Plano convex |
Question 76 |
The mirror that diverges the light rays is ________
concave | |
convex | |
plane | |
none |
Question 77 |
The centre of the sphere, of which a spherical mirror is a part is called ________
pole | |
radius of curvature | |
focus | |
centre of curvature |
Question 78 |
The centre of the reflecting surface of a spherical mirror is ________
centre of curvature | |
focus | |
pole | |
radius of curvature |
Question 79 |
The point at which the rays are converged or diverged by a mirror is ______
pole | |
principal focus | |
principal axis | |
centre of curvature |
Question 80 |
The radius of curvature of the spherical mirror is equal to ______
focal length | |
twice the focal length | |
thrice the focal length | |
half of the focal length |
Question 81 |
Which mirror is called converging mirror?
plane | |
convex | |
concave | |
plane concave |
Question 82 |
A virtual and equal sized image is formed by _______
concave mirror | |
convex mirror | |
plane mirror | |
none |
Question 83 |
To form a real image, the mirror required is ______
concave | |
convex | |
plane | |
none |
Question 84 |
A virtual and enlarged image is formed by ________
convex mirror | |
concave mirror | |
plane mirror | |
both concave and convex mirror |
Question 85 |
- A real image is always inverted
- A virtual image is always erect
only I is true | |
only II is true | |
both I and II are true | |
neither is true |
Question 86 |
To form a virtual image, we use_____
only convex mirror | |
only concave mirror | |
either convex or concave mirror | |
plane mirror |
Question 87 |
According to ________ of light, angle of incidence is equal to angle of reflection.
refraction | |
dispersion | |
reflection | |
total internal reflection |
Question 88 |
A coin at the bottom of a bucket filled with water is appeared to be raised due to _____
dispersion | |
reflection | |
diffraction | |
refraction |
Question 89 |
To obtain magnified, erect image in a concave mirror, object should be held______
at pole (P) | |
at focus(F) | |
beyond 2F | |
between O and (F) |
Question 90 |
An object is placed at focus of a concave mirror, image is formed at ________
infinity | |
behind the mirror | |
focus | |
centre of curvature |
Question 91 |
The image formed by a concave mirror is real, inverted and of same size as that of the object. The position of the object is _________
at F | |
at C | |
between F and 2F | |
beyond 2F |
Question 92 |
An object is placed between F and 2F of a concave mirror, image will be formed ________
at infinity | |
beyond F | |
beyond 2F | |
between F and O |
Question 93 |
To obtain same, real and inverted image in concave mirror object should be placed _______
at F | |
at 2F | |
beyond 2F | |
between F and optical centre |
Question 94 |
When an object is placed between F and optical centre O in concave mirror the image formed will be _______
real-inverted and diminished | |
virtual- inverted and diminished | |
virtual-erect and diminished | |
virtual-erect and enlarged |
Question 95 |
The mirror is used _________
to get powerful parallel beam of light | |
to obtain a magnified images | |
to produce heat | |
all the above |
Question 96 |
Concave mirror is used_______
to get powerful parallel beam of light | |
to obtain magnified images | |
to produce heat | |
all the above |
Question 97 |
Which mirror is used in solar furnaces?
concave | |
convex | |
plane | |
none |
Question 98 |
The image formed by a spherical is virtual, erect and smaller in size, whatever be the position of the object, the mirror is _____
concave | |
convex | |
plane | |
both convex and concave |
Question 99 |
When an object is placed at the principal focus of the convex lens the image formed is ______
enlarged | |
diminished | |
highly enlarged | |
highly diminished |
Question 100 |
In automobiles, the mirror used to see the rear view is ________
concave | |
plane | |
convex | |
parabolic mirror |
Question 101 |
Convex mirrors are preferred because_________
it gives powerful parallel beams | |
it concentrates the light | |
always give an erect image | |
it gives real inverted image |
Question 102 |
Which mirror is used by ENT specialists and dentists?
concave mirror | |
plane | |
convex | |
parabolic |
Question 103 |
Which mirror is used as shaving mirror?
concave | |
plane | |
convex | |
parabolic |
Question 104 |
The mirror used by a dental surgeon is ______
concave | |
plane | |
convex | |
both concave and convex |
Question 105 |
All the distances measured to the right of the origin is taken as ______
positive | |
negative | |
either positive or negative | |
none |
Question 106 |
The distance of the image is from the pole of the mirror is called ______
a
focal length | |
image distance | |
object distance | |
principal axis |
Question 107 |
The distance of the principal focus from the pole is called _______
focal length | |
image distance | |
object distance | |
principal axis |
Question 108 |
Object distance is the distance between ______
pole and the image | |
pole and the object | |
principal focus and the pole | |
none of the above |
Question 109 |
. For a concave mirror, value of v is positive, if image formed is _______
virtual | |
real | |
diminished | |
magnified |
Question 110 |
Which mirror has a negative focal length?
Plane | |
Concave | |
Convex | |
All the above |
Question 111 |
Which mirror has a negative value of v and forms a real image?
Plane | |
Concave | |
Convex | |
None |
Question 112 |
For a convex mirror, the image distance is always ________
positive | |
negative | |
small | |
large |
Question 113 |
The distance of the image of an object in spherical mirror is measured from the______
focus | |
centre of curvature | |
pole | |
infinity |
Question 114 |
Which of the following represent the unit of magnification?
dioptere | |
metre | |
decimetre | |
no unit |
Question 115 |
Refraction takes place through _________
opaque | |
transparent | |
metals | |
none |
Question 116 |
Magnification of a concave mirror is ________
less than one | |
more than one | |
more or less than one | |
infinity |
Question 117 |
A convex mirror has a magnification which is always ________
equal to one | |
less than one | |
more than one | |
infinity |
Question 118 |
When a ray of light travels from water to glass, it bends______
towards normal | |
away from normal | |
neither towards nor away from normal | |
along the normal |
Question 119 |
Light travels fastest in ________
vacuum | |
air | |
glass | |
diamond |
Question 120 |
No refraction occurs when a ray goes from _______
rarer to denser medium | |
denser to rarer medium | |
one medium to other medium of same optical density | |
none |
Question 121 |
The angle between the normal and the refracted ray is called______
angle of reflection | |
angle of refraction | |
angle of incidence | |
angle of deviation |
Question 122 |
The second law of refraction is stated by ________
C.V.Raman | |
Newton | |
Snell | |
Gallile |
Question 123 |
Value of refractive index does not depend on ________
angle of incidence | |
substance of medium | |
temperature | |
speed of light in medium |
Question 124 |
An imaginary straight line passing through the two centres of curvature of a lens is _____
focal length | |
radius of curvature | |
aperture | |
principal axis |
Question 125 |
The effective diameter of length of a lens from whose refraction takes place is called _______
focus | |
centre of curvature | |
aperture | |
optic centre |
Question 126 |
. In case of thin lenses, radius of curvature is _________
greater than aperture | |
lesser than aperture | |
equal to aperture | |
very much lesser than aperture |
Question 127 |
The central point of a lens is called ________
centre of curvature | |
optical centre | |
principal focus | |
aperture |
Question 128 |
Optic centre is ________
necessarily at the centre of lens | |
necessarily inside the lens | |
necessarily on principal axis | |
can be anywhere |
Question 129 |
The light rays passing through the optic centre will_______
converge | |
diverge | |
reflect | |
emerge undeviated |
Question 130 |
A ray passing through the focus of the less will ______
converge | |
diverge | |
emerges parallel to the principal axis | |
none |
Question 131 |
An object is placed away from 2F of a convex lens, image is formed ______
at F | |
between F and 2F | |
at F | |
at infinity |
Question 132 |
Virtual, erect and enlarged image is produced by convex lens when the object is placed ______
beyond 2F | |
between F and 2F | |
at F | |
between F and optic centre(O) |
Question 133 |
If the object at 2F in case of a convex lens, image is necessarily at _________
F | |
2F | |
infinity | |
O |
Question 134 |
The image formed by a convex lens, when the object is placed between F and 2F is ______
real-inverted and diminished | |
real-inverted and of same size | |
real- inverted and enlarged | |
virtual- erect and enlarged |
Question 135 |
A convex lens does not produce _______
virtual diminished image | |
virtual enlarged image | |
real magnified image | |
real diminished image |
Question 136 |
For a convex lens, as the object distance(u) increases, the image distance(v)________
remains constant | |
increases | |
decreases | |
is infinity |
Question 137 |
Which lens is used as a magnifying glass?
convex | |
concave | |
biconcave | |
Plano concave |
Question 138 |
A concave lens is a_____
diverging lens | |
converging lens | |
magnifying lens | |
plane lens |
Question 139 |
The image formed by concave lens is always_______
real-inverted and diminished | |
real-inverted and of same size | |
real- erect and enlarged | |
virtual-erect and diminished |
Question 140 |
Which statement is correct about a concave lens__________
object distance (u) is negative | |
focal length is negative | |
image distance(v) is negative | |
all the above |
Question 141 |
The reciprocal of focal length of a lens is _______
principal focus | |
power | |
magnification | |
image distance |
Question 142 |
The SI unit of power of lens is ______
metre | |
decimetre | |
dioptre | |
no unit |
Question 143 |
The focal length of lens is 1 metre, then its power is _________
1 dioptre | |
1 metre | |
1 decimetre | |
1 |
Question 144 |
Image of real object formed by concave lens is ________
always real | |
always virtual | |
sometimes real | |
sometimes virtual |
Question 145 |
Various colours in a rainbow is due to _________
reflection | |
refraction | |
deviation | |
dispersion |
Question 146 |
A prism is a transparent medium bounded by two ______
non-parallel plane surfaces | |
parallel plane surfaces | |
spherical surfaces | |
concave surfaces |
Question 147 |
Dispersion takes place due to ________
different speed of different colours of light | |
all colours of light travel with same speed | |
reflection by the prism | |
transparent medium |
Question 148 |
Spectrum is the band of distinct _________
7 colours | |
9 colours | |
5 colours | |
8 colours |
Question 149 |
Twinkling of stars is due to ______
reflection | |
dispersion | |
atmospheric refraction | |
none of the above |
Question 150 |
White light is made up of _______
seven colours | |
six colours | |
all colours | |
no colour |
Question 151 |
Light enters the eye through _______
pupil | |
iris | |
cornea | |
retina |
Question 152 |
In a human eye, the image is formed at ________
pupil | |
iris | |
cornea | |
retina |
Question 153 |
The amount of light entering the eye is adjusted by ________
pupil | |
iris | |
cornea | |
retina |
Question 154 |
The size of pupil of the eye is adjusted by ______
cornea | |
iris | |
retina | |
ciliary muscles |
Question 155 |
Eye lens is a _______
double convex lens | |
double concave | |
Plano convex lens | |
Plano concave lens |
Question 156 |
The eye lens forms an image on the retina is_______
inverted – real image | |
erect- real image | |
virtual erect image | |
virtual-inverted image |
Question 157 |
A person can see an object, when its image is formed ______
in front of retina | |
in front of cornea | |
away from retina | |
on the retina |
Question 158 |
. The least distance of distinct vision is _______
25 cm | |
35cm | |
20 cm | |
infinity |
Question 159 |
. Focal length of eye lens increases permanently or contraction of the eye ball results in __________
myopia | |
presbyopia | |
hypermetropia | |
astigmatism |
Question 160 |
A convex lens is used to rectify ___
myopia | |
presbyopia | |
hypermetropia | |
astigmatism |
Question 161 |
Ageing results in _______
myopia | |
presbyopia | |
hypermetropia | |
astigmatism |
Question 162 |
Elongation of the eye ball results________
myopia | |
presbyopia | |
hypermetropia | |
astigmatism |
Question 163 |
Which lens is used to rectify myopia?
convex | |
concave | |
bifocal | |
cylindrical |
Question 164 |
Myopia is also known as_______
near sightedness | |
far sightedness | |
refractive defects | |
none |
Question 165 |
An old person cannot see nearby and distant objects can use ____
convex | |
concave | |
cylindrical | |
bifocal |
Question 166 |
. Presbypia arises due to ____
contraction of eye ball | |
elongation of eye ball | |
diminishing flexibility of eye ball | |
none of the above |
Question 167 |
The person cannot donate eyes, who is suffering from ________
asthma | |
diabetes | |
hypertension | |
leukaemia |
Question 168 |
Focal length of the eye lens is ________
fixed | |
variable | |
either fixed or variable | |
neither fixed nor variable |
Question 169 |
Variable focal length of eye lens is responsible for _______
accommodation of eye | |
colour blindness | |
persistence of vision | |
least distance of distinct vision |
Question 170 |
When we go out in the bright sunlight, the pupil of the eye_______
contracts | |
expands | |
sometimes expands | |
neither contracts nor expands |
Question 171 |
Which telescope was carried by a space shuttle?
astronomical | |
Hubble | |
terrestrial | |
none |
Question 172 |
Hubble’s telescope is used _______
to measure the expansion of universe | |
to find block holes | |
to observe distant supernova | |
all the above |
Question 173 |
The radius of curvature of a concave mirror is -10 cm. its focal length is ___
20 cm | |
-5 cm | |
5 cm | |
10 cm |
Question 174 |
Concave mirror produces 10 cm long image of an object of height 2 cm. The magnification is ________
5 | |
20 | |
10 | |
2 |
Question 175 |
Which of the following controls the pupil of the human eye?
cornea | |
citrary muscles | |
Iris | |
Retina |
Question 176 |
A device which converts electrical energy into mechanical energy is _______
Generator | |
Motor | |
Transformer | |
Power supply |
Question 177 |
The defect myopia can be corrected by using a _______
convex lens | |
concave lens | |
concave mirror | |
convex mirror |
Question 178 |
The defect hypermetropia can be corrected by using a _______
convex lens | |
concave lens | |
concave mirror | |
convex mirror |
Question 179 |
The amount of induced e.m.f when the magnetic field linked with the coil changes is ______
magnetic induction | |
current produced | |
e.m.f produced | |
changing current |
Question 180 |
______ discovered electromagnetic induction.
Oersted | |
Faraday | |
Edison | |
Newton |
Question 181 |
The type of mirror used in Hubble space telescope is _______
Hyperbolic mirror | |
Concave mirror | |
Convex mirror | |
Plane mirror |
Question 182 |
Match the following
- Convex mirror a. Concave lens
- Radius of curvature of a spherical mirror b. Metre
- Focal length c. Reflecting surface is curved outward
- Myopia d. 2 x focal length
1 4 2 3 | |
2 1 3 4 | |
4 3 1 2 | |
3 2 1 4 |
Question 183 |
Match the following
- Beyond 2F a. Infinitely large
- At 2F b. Enlarged
- At principal focus F c. Same size
- Between F and 2F d. Diminished
4 3 1 2 | |
2 1 3 4 | |
4 3 2 1 | |
3 2 1 4 |
Question 184 |
Match the following
- Reciprocal of focal length a. Metre
- Search light and vehicles b. Telescope
- Focal length c. Power of a lens
- Supernovae d. Convex lens
3 4 1 2 | |
2 1 3 4 | |
4 3 2 1 | |
4 3 1 2 |
Question 185 |
Match the following
- Iris a. Sending signal to the brain
- Optic nerves b. A delicate membrane
- Retina c. Controls the amount of light entering
- Pupil d. A dark muscular diaphragm
3 4 1 2 | |
2 3 4 1 | |
2 1 3 4 | |
4 3 1 2 |
Question 186 |
Match the following
- Concave mirror a. Dispersion
- Refraction b. Virtual and erect image
- Concave lens c. Snell’s law
- Prism d. To produce heat in solar furnace
4 3 1 2 | |
2 3 4 1 | |
2 1 3 4 | |
4 3 2 1 |
Question 187 |
Match the following
- Electric motor a. Converts mechanical energy into electrical energy
- Electric generator b. Generate electrical signal when illuminated
- Height sensitive cells c. Black holes
- Hubble’s observations d. Converts electrical energy into mechanical energy
4 3 1 2 | |
2 3 4 1 | |
2 1 3 4 | |
4 3 2 1 |
Question 188 |
A | |
B | |
C | |
D |
Question 189 |
A | |
B | |
C | |
D |
Question 190 |
A | |
B | |
C | |
D |
Question 191 |
A | |
B | |
C | |
D |
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There are 191 questions to complete.
