Question # 1

The gravity does no work, when the body moves:

Choose an answer

Horizontally

Vertically upwards

Vertically downward

At an angle of 45o with horizontal

The temperature scale approved in SI units is:

Choose an answer

Calslus scale

Kelvin scale

Fehrenhelt scale

None of these

An electron and a proton are projected at right angles to a uniform magnetic field with

Choose an answer

the electron trajectory will be less curved than proton’s trajectory

the electron trajectory will be more curved than proton’s trajectory

) both trajectories will be equally curved

) both particles continue to move along a straight lins

A body crosses the topmost point of a vertical circle with critical speed. Itscentripetal acceleration, when the string is horizontal will be

Choose an answer

4g

3g

g

6g

On slightly disturbing a body which is an unstable equilibrium, its center of gravity

Choose an answer

rises

falls

remains constant

first rises then falls

A pulsating DC can be converted into constant voltage by using

Choose an answer

Filter

Full wave rectifier

Half wave rectifie

Bridge rectifier

A radioactive substance has a half-life of 4 months. Three-fourths of the substance will decay in:

Choose an answer

5months

6months

8months

7months

The energy which an -e acquires when accelerated through a potential difference of 1 volt is called?

Choose an answer

1 Joule

1 Electron volt

1 Erg

1 Watt

G.P Thomson revealed:

Choose an answer

Particle nature of electron

Dual nature of electron

Wave nature of electron

Electromagnetic nature of electron

The energy of photon of wavelength 1240 nm is:

Choose an answer

0.5 eV

1.0 eV

1.5 eV

2.0 eV

In which of the following, Doppler’s effect is not applicable?

Choose an answer

To find speed of satellite

To find objects under water

To find speed of star

To tune a musical instrument

One degree of thermodynamics scale of temperature is called:

Choose an answer

Celsius

Fahrenheit

Kelvin

Radian

Two 8 N forces act on each end of the beam of length 0.60m. Two forces are parallel and acting opposite to each other, the angle between the force and beam is 60o , what is the torque of the couple exerted on the beam:

Choose an answer

2.4 Nm

4.2 Nm

4.8 Nm

9.6 Nm

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

Choose an answer

Force per unit volume

Energy per unit area

mass per unit volume

None of these

According to boyle's law, volume of a given mass of a gas is

Choose an answer

Inversely proportional mass at constant pressure

Directly proportional to pressure at constant temprerature

Inversely proportional pressure at constant temprature

None of these

A man M₁ of mass 80 kg runs up a staircase in 15s. Another man M₂ also of mass 80 kg runs up the same staircase in 20s. The ratio of the power developed by them will be

Choose an answer

1

4/3

16/9

none of these

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

Choose an answer

Isochoric process

isobaric process

Adiabatic process

Isothermal process

The maximum energy of the photoelectrons depends upon:

Choose an answer

Frequency of incident light

Intensity of incident light

Nature of metal

Both (a) & (c)

The energy stored in wound watch spring is

Choose an answer

K.E.

P.E.

heat energy

chemical energy

Light of frequency 2 times the threshold frequency is incident on the metalsurface. Ifthe frequency is by quartered and intensity is doubled, the photoelectric becomes

Choose an answer

Quadrupled

Zero

Doubled

Halved

In an explosion a body breaks up into two pieces of unequal masses. In this:

Choose an answer

Both parts will have numerically equal momentum

Lighter part will have more momentum

Heavier part will have more momentum

Both parts will have equal kinetic energy

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

Choose an answer

Will be different

Will depend on their masses

Will be same

Will depend upon the place of their projection

What will be the number of photons emitted per second by 25 W source of monochromatic light of wavelength 600 nm:

Choose an answer

7.5 × 1017

7.5 × 1019

5.5 × 1019

5.5 × 1017

The momentum of a particle is numerically equal to its K.E. What is the velocity of a particle?

Choose an answer

9 ms^-1

3 ms^-1

2 ms-1

1 ms^-1

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

Choose an answer

Moving away from the earth

Moving towards the earth

Stationary

Revolving around the planet

A closed organ pipe and an open organ pipe have their first overtones of identicalfrequency. Their respective lengths are in the ratio:

Choose an answer

1 : 2

4 : 3

2 : 3

3 : 5

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

Choose an answer

Moving with zero acceleration

Moving with constant velocity

Covering equal displacement in equal intervals of time

All of these

Which of the following is a unit of energy?

Choose an answer

unit

whatt

Horse Power

None of the above

A thorium nucleus is formed when a uranium nucleus emits an 𝑎 −particles. Atomic number of thorium is :

Choose an answer

23

60

90

70

A machine gun fires ‘n’ bullets per second and the mass of each bullet is m. If v is the speed of each bullet then the force exerted on the machine gun is:

Choose an answer

mng

mnv

mnvg

mnv/g

Davisson and Germer received the Nobel prize for their work on:

Choose an answer

Wave nature of particle

Corpuscular nature of wave

Dual nature of particle

All of them

Charge on a capacitor is 50C. if voltage applied across its plates is 10V then its capacitance:

Choose an answer

5F

0.02F

500F

0.2F

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

Choose an answer

heat energy

electrical energy

nuclear energy

mechanical energy

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

Choose an answer

40 N-m

100 N-m

50 N-m

150 N-m

In uniform circular motion, the factor that remains constant is

Choose an answer

Linear velocity

Centripetal force

Acceleration

speed

De-Broglie received the Nobel prize in

Choose an answer

1929

1937

1928

1924

A ball is thrown vertically upwards. Neglecting air resistance, which statement is correct?

Choose an answer

The kinetic energy of the ball is greatest at the greatest height attained

The potential energy of the ball increase uniformly with time during the ascent

By the principle of conservation of momentum. The momentum of the ball is constant throughout its motion

By the principle of conservation of energy, the total energy of the ball is constant throughout its motion

When two semiconductors of p- and n-type are brought into contact, they from a p-n junction which act like a:

Choose an answer

Conductor

Amplifier

Oscillator

Rectifier

A diode characteristics curve is a graph plotted between;

Choose an answer

Current and time

Voltage and time

Voltage and current

Forward voltage and reverse current

Where in standing wave, do the vibrations of the medium occur?

Choose an answer

Only at the nodes

Only at the antinodes

At all points between the nodes

At all points between the antinodes

The same retarding force is applied to stop a train. The train stops after 80 m. If the speed is doubled, then the Stopping distance will be:

Choose an answer

The same

Doubled

Halved

Four times