Question # 1

Two astronauts in a satellite must have

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Same masses

Same real weights

Same apparent weights

None of these

Nuclear fission experiments show that the neutrons the uranium nuclei into two fragment of about the same size. This process is accompanied by the emission of several:

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Protons and positrons

𝛼 −partilces

neutrons

Protons and 𝛼 −partilces

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

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

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 efficiency of half wave rectifier is:

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25.6%

1.2%

40.6%

66.6%

Rest mass energy of electron is:

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1.02 MeV

0.51 MeV

931 MeV

200 MeV

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

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

The number of molecules in one mole of gas is equal to:

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Avogadro number N_A

Gas constant R

Boltzmann constant k

None of these

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

A 4 m long string fixed at its ends resonate in 4 segments. The wavelength of the waveis:

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4m

0.5m

2m

0.25 m

Two point charges repel each other with a force of 4× 𝟏𝟎−𝟓 newton at a distanceof meter. Two charges are

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Both positive

Alike

Both Negative

Unlike

When an electron in an atom goes from a lower to higher its:

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K.E. increases, P.E. decreases

K.E. increases

P.E increases

K.E. decrease, P.E. increases

A charged conductor has charged on its:

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Outer surface

Surrounding surface

Inner surface

Middle point

Steam engine is:

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An optical system

A thermal system

A thermodynamic system

None of these

The energy of photon of wavelength 1240 nm is:

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0.5 eV

1.0 eV

1.5 eV

2.0 eV

A photo cell is based on:

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Compton effect

Pair production

Photo cell

All of these

The uranium Nucleus 𝟐𝟑𝟖 𝑼 undergoes successive decays, emitting respectively 𝑎 − 𝒓𝒂𝒚,𝖰 − 𝒓𝒂𝒚 𝒂𝒏𝒅 − 𝒓𝒂𝒚𝒔. What is the atomic number and atomic mass of the resulting nucleus:

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90, 238

91, 234

92, 236

92, 238

Petrol engine coverts ____________ of available heat energy into work.

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20% to 25%

25% to 30%

30% to 35%

35% to 40%

The diode charactristics curve is plot between

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I & t

V& t

V& I

None

Which one is the case when the wavelength is actually changed?

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When source move relative to observer

When observer move relative to source

When observer moves around a stationary source at the center of circle

When the relative displacement between source and observer is zero

A sonar depth finder in a boat uses sound signals to determine the depth of water. Fourseconds after the sound leaves the boat it returns to the boat because of reflection fromthe bottom. Assume the speed of sound in water is 1,460 meters per second. The depth of the water is, in meters, :

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2,200

4,800

4,400

2,920

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

A straight current carrying conductor experiences maximum forces in a uniform magnetic field when it is placed:

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Parallel to the field

Perpendicular o the field

At an angle of 45 to the field

None of these

A body is dropped from a height of 20 m and rebounds to a height of 10 m. the loss of energy is:

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10%

45%

50%

75%

In case of planets the necessary acceleration is provided by

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Gravitational force

coulomb force

frictional force

centripetal force

Truth of kinetic energy theory is confirmed by:

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Diffusion of gases

Brownian motion

Both A and B

None of these

During a negative β-decay

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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

If C_vdonotes molar specific heat at constant volume and𝜟 T is the change in temperature, then C_v𝜟T gives:

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Volume

Pressure

Energy

Entropy

An electron and a proton are accelerated through the same potential. If their masses are me and mp respectively, then the ratio of their de-Broglie wavelength is:

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1

mp/me

me/mp

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

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

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Moving with zero acceleration

Moving with constant velocity

Covering equal displacement in equal intervals of time

All of these

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

A pure semiconductor has:

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An infinite resistance at 0^oC)

A finite resistance which does not depend upon temperature

A finite resistance which decreases with temperature

A finite resistance which increase with temperature

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

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1 : 2

4 : 3

2 : 3

3 : 5

The fundamental frequency of a closed organ pope is 50 Hz. The frequency ofsecond over tone is

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100hz

150hz

60hz

250hz

Ratio of dimension of K.E and power is:

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1:1

T:1

1:T

M:J

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

An electron in the n=1 orbit hydrogen atom is bound by 13.6 eV. If a hydrogen atom is in the n=3 state, how much energy is required to ionize it:

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13.6 eV

4.53 eV

3.4 eV

1.51eV

The relationship between Boltzmann constant K with R and N_Ais given as:

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k = RN_A

k = R/N_A

k = NR/N_A

None of these