Question # 1

A body revolved around the sun 27 times faster then the earth what is the ratioof their radii

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1/27

1/4

1/9

1/3

A listener observes the frequency “f” of stationary source. If it move toward with 3 times of velocity of sound. Then the apparent frequency of the sound will be

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f

3f

f/2

4f

At constant temperature, if the density of the gas is increased, its pressure will:

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Decrease

Increase

Remain unchanged

None of these

The unit Compton wavelength is same as:

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Compton wavelength

Compton frequency

Compton shift

Both (a) & (b)

Capacitor stores energy in the form of :

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Electric field

Both of these

Magnetic field

Gravitational field

A stationary wave is established in a string which vibrates in four segments at afrequency of 120 Hz. Its fundamental frequency is:

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15Hz

60Hz

30Hz

430Hz

Tick which of the following is not state variable:

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Heat energy

Pressure

Entropy

Volume

In order to perform experiment, Davisson and Germer used accelerating voltage of:

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54V

120V

220V

400V

If a molecule with momentum mv strikes a wall and rebound then the change in momentum will be:

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-2 mv

Zero

2 mv

mv

Electric current is defined as:

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Flow of charges through conductor

Rate of flow of charges through conductor

Flow of electrons

Flow of protons

In photoelectric effect, electrons are emitted:

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Slowly

Intermittently

Both (a) & (b)

Instantly

Two bodies moving towards each other collide and move away in opposite directions. There is some rise in temperature of bodies because a part of the kinetic energy is converted into

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heat energy

electrical energy

nuclear energy

mechanical energy

In electron microscope, we use high speed electrons because them

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Penetration power is higher

Wavelength is smaller

Frequency is smaller

K.E is smaller

The magnetic field due to the electric current in a conducting wire is:

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Towards the centre of the conducting wire

Circular around the conducting wire

In the direction of the electric current

In the direction opposite to the electric current

A progressive sound wave is a means of transferring energy. A progressive sound waveof constant frequency is generated in air. The intensity of energy transfer is directlyproportional to another of the wave parameters. Which of the following is correct?

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Intensity 𝖺 (𝑎𝑚𝑝𝑙𝑖𝑡𝑢𝑑𝑒)²

Intensity 𝖺 (𝑝𝑒𝑟𝑖𝑜𝑑𝑖𝑐 𝑡𝑖𝑚𝑒)²

Intensity 𝖺 (𝑠𝑝𝑒𝑒𝑑)²

Intensity 𝖺 (𝑤𝑎𝑣𝑒𝑙𝑒𝑛𝑔𝑡ℎ)²

When ultraviolet rays are incident in metal plate, then photoelectric effect does not occur. It occurs by the incidence of:

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x-rays

Infrared rays

Radio wave

Greenhouse effect

In a full wave rectifier, the diode conducts during

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Both halves of the input cycle

A portion of the positive half cycle of the input

Positive half cycle of the input

Both halves of the input cycle

Kinetic energy of a body moving with speed of 10 ms-1 is 30 J. If its speed becomes30 ms-1 then its K.E becomes

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10J

270 J

90J

180 J

The energy of photon of wavelength 620 nm is:

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0.5 eV

1.0 eV

1.5 eV

2.0 eV

The number of electrons emitted depend upon

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Colour of target surface

Shape of surface

Frequency of incident light

Intensity of incident light

The de-Broglie wavelength of the particle of mass m and energy E is:

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ℎ

𝜆 = ℎ√2𝑚𝐸

𝜆 = 1

The momentum of the moving photon is:

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Zero

ℎ

𝜆

ℎ𝜆

If velocity time graph is a straight line parallel to time axis then body is

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Moving with zero acceleration

Moving with constant velocity

Covering equal displacement in equal intervals of time

All of these

In nuclear fission reaction, when the products are 140X and 94Sr, the number of neutrons emitted is

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1

2

5

9

Bats navigate and find food by:

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Ultrasonic

Echolocation

Refraction

A total charge of 100C flows through 12W bulb in a time of 50 second. Which is the potential difference across the bulb during this time?

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0.12V

6.0V

2.0V

24V

A circuit that converts Pulsating DC into smooth DC contain :

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Filter

Capacitor

Inductor

LC circuit

When resistances are connected in Parallel, the effective resistance will be

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Product of the reciprocals of the individual resistances

Product of the individual resistances

Sum of the reciprocals of the individual resistances

Sum of the individual resistances

The equation PVr = Constant applies to:

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Isothermal process

Adiabatic process

Isobaric process

None of these

If P is the pressure and V is the volume, Then PV will represent:

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Power

Work

Force

None of these

When a gas is compressed:

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Its internal energy decreases

Its temperature decreases

Its temperature increases

None of these

In full wave rectification, the output DC voltage across the load is obtained for.

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The positive half cycle of input AC only

The negative half cycle of input AC

The completes cycle of input AC only

All of the above

Beta particles have less ionizing power than that of alpha particles because:

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Their smaller energy

Their smaller mass

Their smaller density

Their smaller charge

Swimming is possible on account of

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1^st law of motion

2^nd law of motion

3^rd law of motion

Newton’s law of Gravitation

What is the resultant force in the diagram shown?

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Zero

6N to left

6N to right

11N to right

Two projectiles ‘A’ and ‘B’ are thrown with same speed but at angle of 40 degree and 50 degree with the horizontal. The horizontal range of ‘A’ will be:

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Equal to that of ‘B’

Greater than that of ‘B’

Less than that of ‘B’

4/5times that of ‘B’

Light of frequency 4f0 is incident on the metal of the threshold frequency f0. The maximum kinetic energy of the emitted photoelectrons is

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3h f0

3/2h f0

2h f0

1/2h f0

A straight current carrying conductor experiences maximum forces in a uniform magnetic field when it is placed:

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Parallel to the field

Perpendicular o the field

At an angle of 45 to the field

None of these

Which statement about geostationary orbit is false?

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A geostationary orbit must be directly above the equator

All satellite in a geostationary orbit must have the same masses

The period of geostationary orbit must be 24 hours

There is only one possible radius for a geostationary

When two objects come to common temperature, the body is said to be in:

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Static equilibrium

Dynamic equilibrium

Thermal equilibrium

None of these

Which of the following statement is true about soft X-rays?

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They have large wavelength

They have high energy

They have low energy

Both A and C