Question # 1

When a particle moves in a uniform circular motion. It has:

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Radial velocity and radial acceleration

Tangential velocity and radial acceleration

Tangential velocity and tangential acceleration

Radial velocity and tangential acceleration

In case of planets the necessary acceleration is provided by

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Gravitational force

coulomb force

frictional force

centripetal force

If source and observer are moving towards each other with same speed and aftercrossing they are receding each other then frequency observed by observer:

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Decreases

Remains constant

Increases

First Increases then decreases

Two artificial satellites of unequal masses are revolving in a circular orbit around the earth with a constant speed. Their time periods:

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Will be different

Will depend on their masses

Will be same

Will depend upon the place of their projection

The spectrum of a star’s light is measured and the wavelength of one of the lines as thesodium’s line is found to be 589 nm. The same line has the wavelength of 497 nm whenobserved in the laboratory. This means the star is

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Moving away from the earth

Moving towards the earth

Stationary

Revolving around the planet

Figure represents a graph of kinetic energy (K) of the photoelectrons (in eV) and frequency (v) for a metal used as cathode in photoelectric experiment. The work function of metal is:

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1 eV

2 eV

1.5 eV

3 eV

. Time rate of change of momentum is equal to

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Force

Impulse

Velocity

Both A and C

In uniform circular motion, the factor that remains constant is

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Linear velocity

Centripetal force

Acceleration

speed

The ratio of angular speeds of minute hand and hour hand of a watch is:

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1: 12

6: 1

12: 1

1: 6

When a person lifts a body from ground work done by lifting force is?

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Positive

Negative

Zero

Half of positive maximum

Two bodies are projected at angle 𝜽 𝒂𝒏𝒅 (𝟗𝟎 − 𝜽) to the horizontal with the same speed. The ratio of their times of flight is:

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sin 𝜃 : 1

cos 𝜃 : 1

sin 𝜃 : cos𝜃

cos 𝜃 : sin𝜃

. A force "F1" acts on a body through distance "S1" in the direction of motion and does work "W1". Similarly another force "F2" act on same body through distance "S2" but in opposite to the direction of motion and does work "W2". Now if F1 = F2 and S1 = S2 then which statement is correct.

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W1 = W2

W2< W2

W1 > W2

W1 = W2= 0

The efficiency of half wave rectifier is:

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25.6%

1.2%

40.6%

66.6%

The pressure exerted on the walls on the vessel by gas molecules is defined as:

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Force per unit volume

Energy per unit area

mass per unit volume

None of these

If a body changes its momentum from 100 N s to 200 N s in 10 s then the unbalanceexternal force responsible to change the momentum is

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5 N

2.5 N

2n

10n

A sonometer wire 100 cm in length has a fundamental frequency of 330 Hz. Thevelocity of propagation of waves along the wire is

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115m/sec

660m/sec

990m/sec

When a gas is compressed:

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Its internal energy decreases

Its temperature decreases

Its temperature increases

None of these

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

The ratio of the longest and shortest wavelength of the Lyman series is approximately:

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4/3

9/4

9/5

16/7

The particles equal in mass or greater than mass of protons are called:

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Leptons

Mesons

Baryons

Quarks

Two bodies are projected at angles  and (90°–) with the horizontal at the same speed.The ratio of their maximum heights is

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1 : 1

1 : tan 

tan² : 1

The fundamental frequency of a closed organ pope is 50 Hz. The frequency ofsecond over tone is

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100hz

150hz

60hz

250hz

Photo cells are used for :

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Security and counting system

Automatic door system

Automatic street lighting

All of these

The energy of photon of energy 1 eV is:

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1240 nm

1040 nm

1000 nm

620 nm

A charge of 2C experiences a force 2000N in a uniform electric field. In this fieldthe potential difference between two points separated by a distance 1cm is

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2V

10V

5V

20V

In which process the change in internal energy of the system is zero:

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Isochoric process

Isobaric process

Adiabatic process

Isothermal process

In a full wave rectifier with input frequency 50Hz. The frequency of pulsating D)C) received as an output across the load is

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50 Hz

100 Hz

500 Hz

zero

A circuit that converts Pulsating DC into smooth DC contain :

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Filter

Capacitor

Inductor

LC circuit

The equation W = ________𝜟U represents:

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Thermal process

adiabatic process

Isobaric process

None of these

A sonar depth finder in a boat uses sound signals to determine the depth of water. Fourseconds after the sound leaves the boat it returns to the boat because of reflection fromthe bottom. Assume the speed of sound in water is 1,460 meters per second. The depth of the water is, in meters, :

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2,200

4,800

4,400

2,920

The only significant motion possessed by the mono-atomic gas molecules is:

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Translatory

Rotatory

Vibratory

None of these

Intensity of light from a point source at the edge of unit sphere will be:

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𝑃

P(4π)

4𝜋

The phenomenon of radioactivity is associated with:

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Fission of nucleus

Disintegration of neutrons

Emission of spectral lines

Spontaneous disintegration of the nuclei of atoms

The angular momentum of a body changes from 30 J-S to 50 J-S in 0.5 sec. The torque acting on it is

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40 N-m

100 N-m

50 N-m

150 N-m

In an 𝑎 −decay:

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The parent and daughter nuclei have same number of protons

The daughter nucleus has one proton more than parent nucleus

The daughter nucleus has two protons less than parent nucleus

The daughter nucleus has two neutrons more than parent nucleus

A force of 6 N act horizontally on a stationary mass of 2kg for 4s. The kineticenergy in joule is

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12

72

56

888

If a car moves with a uniform speed of 2 ms-1 in a circle of radius 0.4m. Its angular speed is

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4 rad. s^-1

1.6 rad. s^-1

5 rad. s^-1

2.8 ms^-1

A whistle is revolved with high speed in a horizontal circle of radius R. to an observer at the centre of the circle the frequency of the whistle will appear to be:

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Decreasing

Increasing

Both

Constant

A long solenoid has 20 turns/ cm. The current necessary to produce a magnetic field of 20 mellites inside the solenoid is approximately:

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1A

2A

4A

8A

The angular analogue of linear displacement is called

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angular velocity

angular displacement

angular momentum

moment of force

The most penetrating radiations out of the following is that of

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𝛾-rays

β-rays

α-particles

X-rays