Question # 1

Tick which of the following is not state variable:

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Heat energy

Pressure

Entropy

Volume

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

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rises

falls

remains constant

first rises then falls

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

Photo cells is a device which convert light into:

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Wave nature

Particle nature

Particle wave nature

Dual nature

A certain noninverting amplifier has R1 of 1 kΩ and R2 of 100 kΩ. The closed-loop voltage gain is ………

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100,000

100

1000

101

In which region of the electromagnetic spectrum does the Lyman series of hydrogen atom lie?

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Infrared

Visible

Ultraviolet

X-rays

The half-life of a radioactive element which has only 1//32 of its original mass left after a lapse of 60 days is:

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12days

10days

22days

36days

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

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1

4/3

16/9

none of these

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

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

For the same value of resistors the output of non-inverting amplifier compared to the output of inverting amplifier is, (ignoring phase difference)

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Greater

Equal

Smaller

Undefined

A non-conducting semiconductor diode is:

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Forward biased

Poorly biased

Reverse biased

None of them

A ball takes ‘t’ second to fall from a height 𝒉𝟏 and ‘2t’ second to fall from a height 𝒉𝟐 then h1/h2 is:

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2

4

0.5

0.25

If the K.E. of a body is increased by 300%, its momentum will increase by:

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100 %

150 %

√300%

175 %

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

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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

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

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

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

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

A wave which consists of a single, non-repetitive disturbance is called a

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Continuous wave

Longitudinal wave

Pulse

Transverse wave

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

The energy of photon of wavelength 620 nm is:

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0.5 eV

1.0 eV

1.5 eV

2.0 eV

In uniform circular motion, the factor that remains constant is

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Linear velocity

Centripetal force

Acceleration

speed

If the distance between the plates of a parallel plates capacitor is increased, its potential will:

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Remain the same

Increase

Decrease

Decrease exponentially

A 50 kg man with 20 kg load on his head climbs up 20 steps of 0.25 m height each. The work done in climbing is

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5 J

350 J

100 J

3430 J

The method by which only one half of A.C cycle is converted into direct current is called

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half wave amplification

half wave rectification

Full wave rectification

full wave amplification

If a source of emf is traversed from positive to negative the potential change will be:

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Positive

Negative

Zero

Constant

Speedometer of an automobile measures

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Average velocity

Instantaneous velocity

Acceleration

Instantaneous speed

A cell of negligible resistance and e.m.f 2 V is connected across a series combination of 2,3 and 5 ohms. The p.d. across the 3 Ω resistor is

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0.6 V

1/3 V

2/3 V

4/3 V

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

Which one is the correct express of de-Broglie equation for the length of atoms of mass m at temp? T(k=Boltzmann’s constant):

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Which row is correct for fission and for fusion?

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Produces larger nuclei

Produces smaller nuclei

A process in which no heat enters or leaves the system is called.

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Adiabatic process

Isothermal process

Isochoric process

None of these

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

With the propagation of longitudinal waves through a material medium, the quantitiestransferred in the direction of propagation are:

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Energy, momentum and mass

Energy and momentum

Energy and mass

Energy

The maximum energy of the photoelectrons depends upon:

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Frequency of incident light

Intensity of incident light

Nature of metal

Both (a) & (c)

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

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

In order to perform experiment, Davisson and Germer used accelerating voltage of:

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54V

120V

220V

400V

The time taken by an engine of power 10 kW to lift a mass of 200 kg to a heightof 40 m is (g + 10ms2)

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2 sec

4 sec

8 sec

16sec

During a negative β-decayv

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An atomic electron is ejected

A neutron in the nucleus decays emitting an electron

An electron which already present within the nucleus is ejected

A part of binding energy of nuclei is converted into electron