Online Test

Question # 1

When a nucleus emits an alpha particle, its charge number is decreases by

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3

2

6

5

Each transmitter propagates radio waves of

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One frequency

Three frequencies

Many frequencies

None of these

Steradian is a unit of

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Radius

Plane angle

Solid angle

None of these

A stethoscope detects the instant at which the external pressure is

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Greater than systolic pressure

Equal to systolic pressure

Lower than systolic pressure

None of these

Which of the following is the smallest unit?

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Millimeter

Angstrom

Fermi

Metre

If we conductor electrons and photons of the same wavelength,then they will have the same

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Velocity

Angular momentum

Energy

Momentum

Electric intensity at a place due to charge conductor is a:

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Scalar quantity

Vector quantity

Semi-vector and semi- scalar

Dimensionless quantity

Both A and D are true

Characteristic X-rays are the X-rays which have

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High energy photons

Specific wavelength

Specific frequencies

All of these

One watt-hour is equivalent to

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3.6 x 10³ joule

3.6 x 10^-3 joule

6.3 x 10³ joule

6.3 x 10^-3 joule

A capacitor is charged with a battery and then it is disconnected A slab of dielectric is now inserted between the plates then

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The charge in the plates reduces and potential difference increase

Potential difference between the plates increases stored energy decreases and charge remains the same

Potential difference between the plates decreases,stored energy decreases and charge remains unchanged

None of the above

Electric potential energy per unit charge gives the expression for

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Electric intensity

Electric flux

Electric potenial

Power

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

In the unit of unified mass scale, the mass of an electron is:

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1.007276u

1.008665u

0.00055u

0.000055u

None of these

A flowing liquid possesses

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K.E

P.E

Pressure Energy

All

The value of coefficient of viscosity in comparison to coefficient of friction is

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Very large

Very small

Nearly same

May be small or large

Half-life of U-239 is

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23.5 S

23.5 mint

23.5 days

23.5 years

How many diodes are used for the full wave rectification is

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Two

Three

Four

None of these

Powered and remote control guided missiles are used for

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long ranges

short ranges

medium ranges

none of them

The angle of scattering for which the Compton shift is maximum

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45^o

90^o

180^o

270^o

The work function of any metal is 4 eV.For emitting photoelectron of zero velocity from the surface of this metal,the wavelength of incident light required must be

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2700 A

1700 A

5900 A

3100 A

Period of audible sound waves is

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1 × 10^-4 sec

1 × 10^-3 sec

1 × 10^-2 sec

1 × 10^-1 sec

The effect of loading the prongs of a tuning fork with wax is to:

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Increase the frequency

Decrease the frequency

Maintain the original frequency

All of these

In X-rays the electromagnetic radiations are emitted when the electrons

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Remains in the shell

Moves with uniform velocity

Accelerated

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

Linear momentum is a vector quantity and has direction of

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Its displacement

Velocity

Acceleration

None of these

Which of the following equation describes the situation when heat is supplied at constant pressure

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ΔU = Cp ΔT

ΔU = Cv ΔT

Qp =Cp ΔT

Qp = Cv ΔT

In case when there is no total displacement and average velocity, then the motion is described by

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Variable velocity

Instantaneous velocity

Initial velocity

None of these

What will be the ratio of the distance moved by a freely falling body from rest in 4^th and 5^th seconds of journey?

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4 : 5

7 : 9

16 : 25

1 : 1

Diffraction of x-rays was first studied by:

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J.J.Thomson

Rutherford

Laue

Bragg

Monochromatic light means the light having

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One color

Single wavelength

Single frequency

All of the above

If a stretched string of length 'I' is plucked from its centre, two waves originate, such that

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both will move towards left

both will move towards right

one towards left and other towards right

any one of them

The orbital radius as the revolving body is revolving is

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Very Smaller

Larger

Smaller

None of these

The magnetic flux also called

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Flue

Magnetic intensity

Flux density

Self inductance

Stress that induces a change in the shape of the body is named as

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Tensile stress

Volumetric stress

Shear stress

None of these

Which one of the following bulbs has the least resistance

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100 W

200 W

300 W

600 W

The half life of uranium - 239 is

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12 minutes

20.4 minutes

23.5 minutes

29.4 minutes

A magnet is moved towards coil (i) quickly (ii) slowly: then the induced charge is:

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Larger in case (i)

Smaller in case (i)

equal in both cases

Larger or smaller depending upon radius of hte coil

Speed of sound in aluminium at 20°C is

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3543 ms^-1

4250 ms^-1

5100 ms^-1

51200 ms^-1

When two waves with same frequency and constant phase difference interfere.

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There is a gain of energy

There is a loss of energy

The energy is redistributed and the distribution changes with time

The energy is redistributed and the distribution remains constant with time

Essential characteristic of equilibrium is:

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Momentum equal to zero

Acceleration equal to zero

Kinetic energy equal to zero

Velocity equal to zero

The angle between two vectors -2î + 3ĵ + k̂ and î + 2ĵ-4k̂ is:

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0°

90°

180°

None of the above