R4RIN – MCQs, Mock Tests | MCAT MCAT Physics Mcq Questions Modern physics

When a pure inductor of inductance L and a pure capacitor of capacitance C are connected in parallel to a sinusoidal potential difference V the potential difference across both L & C will be

1. Same
2. Different
3. At L will be more than at C
4. At L will be less than at C

✅ Correct Answer: 1

An alternating potential difference is connected across a pure resistor and the frequency of the supply is varied but the rms value of the voltage is kept constant. The mean rate of heat dissipated from the resistor is

1. Directly proportional to f
2. Directly proportional to ??f
3. Directly proportional to f2
4. Inversely proportional to f

✅ Correct Answer: 3

What is the self inductance of a coil in which an induced emf of 2V is set up when the current changes at the rate of 4 As-1?

1. 0.5 mH
2. 0.5H
3. 2.0H
4. 8.0H

✅ Correct Answer: 2

The frequency of a circuit consisting of a capacitance C and a resistor R is

1. C/R
2. R/C
3. 1/RC
4. 1/ ??RC

✅ Correct Answer: 3

A 10? electric heater is connected to a 220V 50Hz mains supply. What is the peak value of the potential difference across the heater element?

1. 220V
2. 220/ ??2V
3. 110V
4. 220 ??2V

✅ Correct Answer: 4

A choke is used as a resistance in

1. DC circuit
2. AC circuits
3. Both AC and DC circuit
4. Full wave rectifier circuit

✅ Correct Answer: 2

At resonance the value of the power factor in an L-C-R series circuit is

1. Zero
2. 2
3. 1
4. not definite

✅ Correct Answer: 3

An A.C series circuit containing 4? resistance and 3-? inductive reactance. The impedance of the circuit is

1. 1?
2. 5?
3. 7?
4. 7/?2?

✅ Correct Answer: 2

An inductive coil has a resistance of 100?. When an AC signal of frequency 1000Hz is fed to the coil the applied voltage leads the current by 45?. What is the inductance of the coil?

1. 10mH
2. 12mH
3. 16mH
4. 20mH

✅ Correct Answer: 3

Choose the correct statement. In the case of AC circuit ohms law holds for

1. Peak values of voltage and current
2. Effective values of voltage and current
3. Instantaneous values of voltage and current
4. All of the above

✅ Correct Answer: 4

The phase angle between the voltage and the current in an AC circuit consisting of a resistance is

1. Zero
2. 45?
3. 90?
4. 180?

✅ Correct Answer: 1

In an LCR series circuit, if V is the effective value of the applied voltage VR is the voltage across R VL is the effective voltage across L & Vc is the effective voltage across C then

1. V = VR+VL+VC
2. V2 = VR2+VL2+VC2
3. V2 = VR2+(VL-VC)2
4. V2 = VL2+(VR-VC)2

✅ Correct Answer: 3

a voltage V = V? cos ?t is applied across a resistor of resistance R the average power dissipated per cycle in the resistor is given by

1. V?/?2R
2. V?/?2?R
3. V?2/?2R
4. V?2/?2?R

✅ Correct Answer: 3

Two identical coaxial circular loops carry equal currents in the same direction. If the loops approach each other the current in

1. Each increases
2. Each decreases
3. Each remains the same
4. One increases whereas that in the other decreases

✅ Correct Answer: 2

An inductor may store energy in

1. its electric field
2. its coils
3. its magnetic field
4. both electric and magnetic fields

✅ Correct Answer: 3

Tick the correct statement

1. the flight path of a vertically falling body appears straight to the stationary observer
2. the flight path of vertically falling body appears parabolic to an observer in uniform relative motion
3. all states of rest and motion are relative and there is no such thing as absolute motion
4. all the above

✅ Correct Answer: 4

Mark the wrong statement.

1. a frame of reference which is either at rest or moves with a constant velocity is called an inertial frame of reference
2. an un-accelerated frame of reference is called an inertial frame of reference
3. all the frames of reference in uniform rectilinear motion are equivalent
4. Newtons laws of motion are valid in an accelerated (non inertial) frame of reference

✅ Correct Answer: 4

The relativistic energy E is equivalent to relativistic mass given by

1. Ec2
2. E/c2
3. E/c
4. c2/E

✅ Correct Answer: 2

An observer shoots parallel to a meter stick at very high (relativistic) speed and finds that the length of meter stick is

1. greater than one meter
2. less than one meter
3. one meter
4. a foolish question

✅ Correct Answer: 2

0.001 kg mass will be equivalent to

1. 2.50 GWh
2. 25.00 GWh
3. 0.26 GWh
4. 250 GWh

✅ Correct Answer: 2

Which one of the following radiations has the strongest photon?

1. T.V waves
2. micro waves
3. X-rays
4. ?-rays

✅ Correct Answer: 4

Tick the right statement.

1. no photo electronic emission takes place if the frequency of radiation however intense it may be is less than a certain critical value called threshold frequency
2. threshold frequency depends upon the nature of the metal surface
3. maximum energy of a photoelectron is a function of frequency rather than intensity of radiation
4. all of the above

✅ Correct Answer: 4

Linear momentum of a photon is

1. zero
2. hv/c2
3. hv/c
4. c2/hv

✅ Correct Answer: 1

A device based on photoelectric effect is called

1. photo sensitive detection
2. photo diode
3. photosynthesis
4. photo cell

✅ Correct Answer: 4

The linear momentum of an X-ray photon of wavelength 0.1A is

1. 6.625x1023N-s
2. 66.25x1023N-s
3. 662.5x1023N-s
4. data is insufficient

✅ Correct Answer: 1

Stopping potential for a metal surface in case of photoelectric emission depends on

1. the threshold frequency for the metal surface
2. the intensity of incident light
3. the frequency of incident light and work function of the metal surface
4. all of the above

✅ Correct Answer: 3

Select an alternative from of uncertainly principle from the following

1. ?? = h/m?c(1-cos ?)
2. ?E . ?t = h
3. mc2 = hv
4. any of above

✅ Correct Answer: 2

The existence of Ether wind was experimentally rejected by

1. equal to its rest mass
2. double of its rest mass
3. infinite
4. zero

✅ Correct Answer: 3

If a material object moves with speed of light its mass becomes

1. equal to its rest mass
2. double of its rest mass
3. infinite
4. zero

✅ Correct Answer: 3

As the temperature of black body is raised the wavelength corresponding to maximum intensity

1. shifts towards longer wavelength
2. shifts towards shorter wavelength
3. remain the same
4. shifts towards longer as well as shorter wavelengths

✅ Correct Answer: 2

Rest mass of a photon is

1. infinite
2. zero
3. very small
4. 1.67 x 10-27 kg

✅ Correct Answer: 2

The name of the photon for quantum of light was proposed by

1. Ampere
2. Plank
3. Thomson
4. Einstein

✅ Correct Answer: 4

Einsteins photoelectric equation is given by

1. 1/2 mvmax2=hf+?
2. 1/2 mvmax2-hf = ?
3. 1/2 mvmax2=hf-?
4. all of above are correct

✅ Correct Answer: 3

In Compton scattering the change in wave length is max if

1. angle of scattering is 90?
2. angle of scattering is 60?
3. angle of scattering is 180?
4. angle of scattering is zero

✅ Correct Answer: 3

Davison Germer experiment indicates

1. interference
2. polarization
3. election diffraction
4. refraction

✅ Correct Answer: 3

A photon is

1. a unit of energy
2. a positively charged particle
3. a quantum of electromagnetic radiation
4. a unit of wavelength

✅ Correct Answer: 3

Which one of the following has the largest energy content?

1. 103 photons of wavelength 2pm (?-rays).
2. 102 photons of wavelength 1nm (x-rays).
3. 106 photons of wavelength 50?m (infrared).
4. 106 photons of wavelength 200nm (UV).

✅ Correct Answer: 1

After traveling through a vacuum a photon of light entering into some transparent denser medium. Thus the energy of light

1. Increases because wavelength decreases
2. Decreases because speed decreases
3. Remains same
4. Increases then decreases

✅ Correct Answer: 3

In a photoelectric effect monochromatic light is incident on a metal surface. If the incident light of twice the intensity but of same wavelength the kinetic energy of the emitted electron

1. Becomes double
2. Remains same
3. Becomes half
4. First increases then decreases because curvilinear graph

✅ Correct Answer: 2

If the wavelength of incident radiation is increased in photoemission then

1. The maximum kinetic energy of the photoelectrons increases.
2. The minimum kinetic energy of the photoelectrons decreases.
3. The minimum kinetic energy of the photoelectrons increases.
4. The average kinetic energy of the photoelectrons decreases.

✅ Correct Answer: 4

A photon of wave length 900nm behaves like a particle of mass

1. 5.53 x 10-36kg
2. 0 kg.
3. 2.46 x 10-36kg
4. 1.84 x 10-44kg

✅ Correct Answer: 3

In Davisson-Germer experiment the diffracted proton from crystal shows

1. Particle property
2. Wave property
3. Light property
4. Quantum property

✅ Correct Answer: 2

If a diffraction grating is placed in the path of a light beam it reveals

1. Wave property
2. Particle property
3. Energy particle
4. Electromagnetic wave property

✅ Correct Answer: 1

In electron microscope we use energetic particles because of

1. Penetrating power is high
2. Kinetic energy is large.
3. Wavelength is very short.
4. All the above reasons.

✅ Correct Answer: 3

In electron microscope electric & magnetic fields are used as

1. Electromagnetic gun.
2. Source of electromagnetic waves.
3. Deflecting charged particle
4. Converging source of electrons.

✅ Correct Answer: 4

A three dimensional image is obtained by

1. Electron microscope
2. Seanning electron microscope
3. Magnetic imaging
4. None of the above

✅ Correct Answer: 2

The uncertainty in momentum & position is due to its

1. Property of matter and radiation.
2. Two dimensional motion.
3. Emission of certain wavelength
4. Very high velocity.

✅ Correct Answer: 1

For confinement of electron in a box of radius 10-14m the electron speed should be

1. 107m/sec
2. Should be greater than speed of light.
3. Be zero
4. Not be wavelike.

✅ Correct Answer: 2

The energy radiated is directly proportional to fourth power of Kelvins temperature is

1. Karl-weins law
2. Rayleigh Jeans law.
3. Stephens law.
4. Plancks

✅ Correct Answer: 3

Compton effect proves the

1. Photon theory of light
2. Dual nature of light
3. Wave nature of light
4. Uncertain nature of light

✅ Correct Answer: 1