Online Test

Question # 1

The force experienced is F = BIL, when a current carrying conductor carrying current I with length 'L' is placed in a magnetic field, will be at

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θ = 0

θ = 90°

θ = 60°

θ = 180°

When the source is moving away from the observer at rest the apparent frequency will be

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Increased

Decreased

Not changed

None of these

The working of a dynamo is based on the principle of:

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Heating effect of current

Magnetic effect of current

Chemical effect of current

electromagnetic induction

Fahrenheit and centigrade (Celsius) thermometers have the same reading at

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-100°C

60°C

40°C

-40°C

The bands below the valence band are

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completely filled and play active part in conduction process

completely filled and plays no part in conduction process

not completely filled and play active part in conduction process

not completely filled and play no part in conduction process

The value of the plank's constant 'h' is given by

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1.6 x 10^-19J

1.67 x 10^-27kg

6.63 x 10³⁴Js

6.63 x 10^-34Js

The value of 'γ' for polyatomic gas is

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1.40

1.67

1.17

1.29

Fission chain reaction is controlled by introducing

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iron rods

cadmium rods

graphite rods

platinum rods

The drift velocity of free electrons in a metallic conductor is

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10^-3 ms^-1

10^-4 ms^-1

10^-5 ms^-1

10^-6 ms^-1

CRO deflects the beam of

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protons

alpha particles

electrons

neutrons

Two parallel wires carrying current in opposite direction

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Repel each ohter

Attract each other

No effect on each other

None of these

Which of these is not a radiation detector?

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Wilson cloud chamber

cyclotron accelerator

Geiger Miller counter

solid state detector

The substances in which atoms are so oriented that the field produced by spin and orbital motion of the electrons might add up to zero, are called

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diamagnetic substances

ferromagnetic substances

paramagnetic substances

all of them

In Compton effect, the law/laws are conserved

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Energy

Momentum

Both

None of these

A prism splits a beam of white light into seven component colors. This is so because

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Phase of different colors is different

Amplitude of different colors is different

Energy of different colors is different

Velocity of different colors is different

Davisson and Germen were the first to demonstrate

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The straight line propagation of light

The diffraction of electrons

The effective mass of electron

The particle nature property

When a stress changes the volume, it is called the

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compressional stress

tensile stress

shear stress

any one of them

Which of them is not a physical quantity

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Density

Impulse

Energy

Kilogram

A person moves 30m north then 20m east then 30√2 m south west His displacement from the original position is

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14 m south west

28 m south

10 m west

15 m east

If the mass of earth becomes four times to its initial value than the value of g will be

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Does not change

Becomes four time

Become one fourth of its initial value

None of these

Typical source of β-particle is

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Radon 222

Cobalt 62

Strontium 94

None of these

In conductors, the valence band and conduction bands are

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Touch each other

Overlapped each other

Largely overlapped

None of these

Neutron was suggested to be in the nucleus by:

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Rutherford in 1920

Bohr in 1913

Dirac in 1928

Anderson in 1932

None of these

Two bodies of 4 g and 16 g have same kinetic energy.What is the ratio of their momenta?

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1 : 4

1 : 2

2 : 1

4 : 1

The penetrating power of X rays increases with

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Decrease in velocity

Increase in velocity

Increase in frequency

Decrease in their intensity

Frequency of red colour as compared to that of violet colour is:

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Equal

Smaller

Greater

None of these

The gas filled in a glass tube in e/m experiment is hydrogen at

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Low pressure

Very low pressure

High pressure

None of these

γ-ray emission from the nucleus of an atom causes a

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change in A

Change in Z only

change in both A and Z

no change in A and Z

Double of Compton s wavelength equal to

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Maximum value if Compton shift

Minimum value of Compton shift

Maximum value of Doppler s shift

Minimum value of Doppler s shift

In diesel engine no sparking device and no need of

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Heavy current unit

Spark plug

Instant starting

None of these

The speed of flying bee is

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1 ms^-1

5 ms^-1

8 ms^-1

10 ms^-1

The energy gap between conduction band and valence band is semiconductor is

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A very narrow forbidden energy gap

A narrow forbidden gap

Of the order of 1 eV

a and b

The ratio of size of the image to the size of the object is called

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Resolving power

Magnification

Power

None of these

The moon produces the tides raise the water in the sea roughly

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Once a day

Twice a day

Several a day

None of these

Even the small viscosity of the air causes a retarding force on car at high speed is

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Small

Large

Very large

None of these

Can a body rotate about its centre of gravity under the action of its weight ?

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No

yes

Both

None of these

The direction of induced current is such that it opposes the very cause that has produced it.This is the law of

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Lenz

Faraday

Kirchoff

Fleming

A switch which is used in voltage measuring part of AVO meter, is called

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selection switch

function switch

range switch

none of them

Torque is a turning effect of a

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Body

Momentum

Force

None of these

Associated with the motion of a driven harmonic oscillator there is a very striking phenomenon known as

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Demping

Resonance

Interference

None of these

Correction factor can be applied to

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Personal error

Systematic error

Random error

All