Question # 1

The coulomb’s law is valid for the charges which are:

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Moving and point charges

Stationary and point charges

Moving and non-point charges

Stationary and large size charges

Carnot engine is ____________ heat engine.

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A reversible

An irreversible

An ideal

Both A and C

A car of 1000kg traveling at 20m/sec rounds a curve of radius 100m. Find the necessary centripetal force

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4 x 10³ kg m/s²

3 x 10³ kg m/s²

5 x 10³kg m/s²

4.5 x 10³kg m/s²

In photoelectric effect, electrons are emitted:

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Slowly

Intermittently

Both (a) & (b)

Instantly

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

Truth of kinetic energy theory is confirmed by:

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Diffusion of gases

Brownian motion

Both A and B

None of these

When a particle moves in a circle the angle between it linear velocity and the angular velocity is always

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0°

180°

90°

none of them

In uniform circular motion, the factor that remains constant is

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Linear velocity

Centripetal force

Acceleration

speed

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

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Only at the nodes

Only at the antinodes

At all points between the nodes

At all points between the antinodes

When passes from medium to another, deviate from its path is called

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reflection

refraction

diffraction

transmission

In the theory of dimensional analysis, heat may be properly represented by:

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ML²T^-2

MT^-2

ML^-1T^-1

None of these

If the radius of the circular path of particle going around the circle is doubled without changing its frequency of rotation, then centripetal force on it is.

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doubled

halved

unchanged

quadrupled

A steady current is flowing in a conductor of non-uniform cross-section. Thecharge passing through any cross-section per unit time is

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Directly proportional to the area of cross-section

Inversely proportional to the area of cross-section

Proportional to square of the area of cross-section

Independent of the area of cross-section

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

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To find speed of satellite

To find objects under water

To find speed of star

To tune a musical instrument

In an ideal gas, the molecules have:

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Kinetic energy only

Potential energy only

Both KE and PE

None 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

When a gas is compressed:

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Its internal energy decreases

Its temperature decreases

Its temperature increases

None of these

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

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

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

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’

Which of the particles, electron, proton and neutron moving with same speed has longest wave length?

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Electron

Proton

Neutron

All have same

The distance between the plates of a charged parallel plate capacitor is 4mm and potential difference is 6 volts. If the distance between the plates is increased to 12mm, then :

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The potential difference of the capacitor will become 18 volts

The P.D become 20 volts

The P.D will remain unchanged

The charge on condenser will reduce to one third

A proton and an 𝑎 − 𝒑𝒂𝒓𝒕𝒊𝒄𝒍𝒆 are accelerated through same voltage, the ratio of their de- Broglie wavelength will be:

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1:2

√2: 1

2√2: 1

2:1

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

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

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Translatory

Rotatory

Vibratory

None of these

There is a certain frequency below which no electrons are emitted from the metal surface, this frequency is known as:

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Critical frequency

Threshold frequency

Maximum frequency

Minimum frequency

When the length and area of cross-section both are doubled, then its resistance:

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Will become half

Will remain the same

Will be doubled

Will become four times

The stopping potential for a certain metal is 10 volt, the max. Energy of emitted electron is:

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10 J

100 J

1.6 × 10-18 J

1.6 × 10-19 J

Work function of all metals varies from 2 eV to 4eV. It is 4.2 eV for Aluminum and2eV for Sodium. If these two metals are illuminated by same light, the thresholdfrequency ofAluminum is

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Less than Sodium

Equal to that of Sodium

Grater than Sodium

Can’t be decided

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

Moving photons posses:

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Energy

Momentum

Wavelength

All of these

An electron is moving towards high potential. Its electrical P.E:

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Increases

Remains constant

Decrease

May increase may decrease

A PN junction diode cannot be use:

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As rectifier

For converting light energy to electrical energy

For getting light radiation

For increasing the amplitude of an ac signal

Real gases strictly obey gas laws at:

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High pressures and low temperatures

Low pressures and high temperatures

High pressures and & temperatures

None of these

In 420 days, the activity of a sample of polonium (Po) fell to one-eight of its initial value. The half-life of polonium is :

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140days

45days

87days

90days

Only those processes are probable to take place for which entropy os the system:

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Increases

Remains constant

Both A and B are correct

None of above

Rest mass energy of electron is:

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1.02 MeV

0.51 MeV

931 MeV

200 MeV

In a photocell, sodium and potassium emit electrons for:

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Visible light

Infrared light

Ultraviolet light

All of these

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:

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The same

Doubled

Halved

Four times