Question # 1

The power output of a full wave rectifier is:

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Equal to H.W.R

Twice of H.W.R

Half of H.W.R

Four times of H.W.R

Work done in raising a box depends on:

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How fast it is raised

The strength of the man

The height by which it is raised

None of the above

A particle executing one dimensional motion, finally comes to rest, what will be the angle between acceleration and displacement during motion:

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0

π

𝜋/2

𝜋/4

If the magnitude of charge on each of two objects is doubled and the distance between them is also doubled then force between them:

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Doubled

Quadrupled

Halved

Remains same

Photo cells are used for :

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Security and counting system

Automatic door system

Automatic street lighting

All of these

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

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23

60

90

70

In a one-dimensional elastic collision, the relative velocity of approach before collision is equal to:

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Sum of the velocities of the bodies

e times the relative velocity of separation after collision

1⁄𝑒 times the relative velocity of separation after collision

relative velocity of separation after collision

The binding energy per nucleon is:

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Greater for heavy nuclei

Least for heavy nuclei

Greatest for light nuclei

Greatest for medium nuclei

A particular wavelength received from a galaxy is measured on earth and isfound to be 5% more than that its wave length on earth. Hence galaxy is

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Moving towards earth

Going away from earth

Stationary with respect to earth

None

Angular displacement in rotational motion is expressed in

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m

m²

Nms-1

Nm s

A body of mass m having an initial velocity v, makes head on elastic collision with a stationary body of mass m. After the collision, the body of mass m comes to rest and only the body having mass M moves. This will happen only when:

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m>>M

m<<M

) m=M

m=1M

For a particle in uniform circular motion the relation a = r 𝑎 of accelerations hold. The acceleration 'a'

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is centripetal acceleration

Is tangential acceleration

is radical acceleration

both A and B

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:

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2.4 Nm

4.2 Nm

4.8 Nm

9.6 Nm

A diode as a rectifier converts:

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A)c into D)c

D)c into A)c

Varying D)c current into constant D)c current

High voltage into low voltage and vice-versa

The radius of orbit of a geostationary satellite depends upon:

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Mass of satellite and its time period

Mass of satellite and mass of earth

Mass of earth, mass of satellite and time period of satellite

Mass of earth and time period of earth

The minimum energy required to remove an electron is called:

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Stopping potential

Work function

Kinetic energy

None of these

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

In photoelectric effect, electrons are emitted with:

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Same energy

Different energies

Both (a) & (b)

Intermittent energies

The reverse process of photo-electric effect is called:

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Pair production

Compton effect

Annihilation of matter

X-rays

A particle revolves round a circular path with a constant speed. The accelerationof the particle is

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A. A long the circumference of the circle

Along the tangent

Along the radius

Zero

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

The magnetic field produced due to the current in a straight wire is proportionalto the :

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Electric current

Conducting material

Length of the wire

Diameter of the wire

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 non-inverting amplifier has infinite input resistance then the voltage gain of noninverting amplifier will be:

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Zero

Infinite

One

100

A diode characteristics curve is a graph plotted between;

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Current and time

Voltage and time

Voltage and current

Forward voltage and reverse current

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

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’

The hydrogen atoms are excited to the stationary state designated by the principal quantum number n=4, the number of maximum spectral lines are observe:

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2

3

4

6

In a half wave rectifier circuit operating from 50 Hz mains frequency, the fundamental frequency in the ripple would be:

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25 Hz

70.7 Hz

50 Hz

100 Hz

The maximum kinetic energy of emitted photoelectrons depends upon:

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The intensity of incident light

Frequency of the incident light

Temperature of the surface

All of above

Temperature of black body radiating at 270c is increased to 327oc, then emittedenergywill increase by

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2 times

12 times

16 times

4 times

In uniform circular motion, the factor that remains constant is:

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Linear velocity

Acceleration

Speed

All of these

A body moves a distance of 10 m along a straight line under the action of a force of 5 N. If the work done is 25 joules, the angle which the force makes with the direction of motion of the body is?

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0 Degree

30 Degree

60 Degree

90 Degree

The law of thermodynamics which discusses the condition under which heat energy is converted into and equivalent amount of work is:

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1st

2nd

3rd

None of these

Bats navigate and find food by:

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Ultrasonic

Echolocation

Refraction

For a gas obeying Boyle's law, if the pressure is doubled the volume becomes:

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One half

Double

Four times

None of these

The direction of force experienced by a moving in a magnetic field will be:

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Parallel to the field

Opposite to the field

Parallel to its direction of motion

Perpendicular to both the field and the velocity vector

A body gets positive charge. It means that:

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It has lost electrons

It has gained positions

It has gained protons

It has gained 𝛼 −particles

Interference and diffraction of light confirms its:

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Particle nature

Dual nature

Wave nature

Electromagnetic nature

As in linear motion force determines linear acceleration where as in circular motion torque determines its

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Angular acceleration

Linear acceleration

Vibratory acceleration

Tangential acceleration

In photoelectric effect, if we increase the frequency of the incident light then of the electrons increased

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Number

K.E

P.E

Frequency