Question # 1

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

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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

The magnitude of potential barrier for Ge is

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0.7 v

0.3 V

7v

3 v

In a gravitational field when work done by gravity is negative then

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P.E increases

P.E decrease

None

P.E remains same

The frequency and work function of an incident photon are n and𝝋𝟎. If f0 is the threshold frequency, then necessary condition for the emission of photo electron is:

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< 𝑓0

𝑓 ≥ 𝑓0

f = 𝑓0/2

None of these

The kinetic energy of a body rotating with an angular speed 𝑚 depends on.

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angular speed

distribution of mass

neither (A) nor (B)

both (A) and (B)

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

Brownian motion confirms the truth of :

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Wave theory of light

Boyle's law

Kinetic theory of gases

Adiabatic process

The force which can do no work on the body on which it acts:

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Frictional force

Elastic force

Gravitational force

Centripetal force

A charged conductor has charged on its:

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Outer surface

Surrounding surface

Inner surface

Middle point

Number of spark plugs needed in diesel engine is:

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Four

Five

Six

None of these

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

A radioactive nucleus can emit:

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Electron

𝛼 particles

Positron

Any of these

select Which one of the following is not performing projectile motion

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A gas filled balloon

) Bullet fired from gun

A football kicked

A baseball shot

A monkey is accelerating down a string whose breaking strength is two third of his weight. The minimumacceleration of the monkey should be

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1/3g

g

2/3 g

0 m/s2

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

If the stone is thrown up vertically and return to ground, its potential energy is maximum

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during the upward journey

at the maximum height

at the bottom

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

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

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

Gain of operational amplifier is independent of;

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Internal structure

External Structure

Batteries

Potential changes

According to Bohr’s theory, a line in the Ballmer series arises when the electron jumps from any of the higher orbits to the orbit with quantum number:

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1

2

3

4

If the temperature difference between hot and cold body is greater the heat engine is:

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Not efficient

Less efficient

More efficient

NOne of above

The activity of a radioactive sample is 1.6 curie and half-life is 2.5 days. Its activity after 10 days will be:

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0.8 Curie

0.1Curie

0.4 Curie

0.16 Curie

Which one of the following particles projected perpendicular to a uniform magnetic field with the same velocity will be deflected least?

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Electron

Proton

Deuton

None of these

Bats navigate and find food by:

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Ultrasonic

Echolocation

Refraction

Continuous spectrum of X-rays id due to an effect known as

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Photoelectric effect

Compton effect

Heisenberg effect

Bremsstrahlung

The relative permittivity of air is

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1

3.7

7.8

1.0006

Diesel engine coverts ____________ of available heat energy into work.

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20% to 25%

25% to 30%

30% to 35%

35% to 40%

. 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

Speedometer of an automobile measures

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Average velocity

Instantaneous velocity

Acceleration

Instantaneous speed

At constant temperature, if the volume of a given mass of a gas is doubled, then the density of gas becomes:

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Double

Remains constant

Half

None of these

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

One degree of thermodynamics scale of temperature is called:

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Celsius

Fahrenheit

Kelvin

Radian

The ideal gas obey gas law at:

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Low tempratures and high pressures

High temperatures and low pressures

All temperatures and pressures

None of these

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

A photo cell is based on:

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Compton effect

Pair production

Photo cell

All of these

To find longest wavelength radiation in Ballmer series, the value of n used is:

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2

3

4

∞

The potential difference between head and tail of an "electric eel" can be upto.

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6V

60V

6000V

600V

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 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

For a particle in circular motion the centripetal acceleration

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may be more or less than its tangential acceleration

equal to its tangential acceleration a

more than its tangential acceleration

less than its tangential acceleration