List of top Physics Questions

A flask contains a monoatomic and a diatomic gas in the ratio of \( 4:1 \) by mass at a temperature of \( 300K \). The ratio of average kinetic energy per molecule of the two gases is:

Electrons are accelerated by 344 volts and reflected from the crystal. The first reflection maximum occurs when glancing angle is 30°. What will be the value of interplanar spacing of the crystal? [Given h=6.62×10^-34 Js, m_e = 9.1x10^-31 kg]

A vertical electric field of magnitude 4.9×10⁵ NC^-1 just prevents a water droplet of mass 0.1 g from falling. What is the charge on the droplet? Take acceleration due to gravity 9.8 ms^-2.

The forbidden energy gaps in conductors, semiconductors and insulators are (E_g)_c, (E_g)_s and (E_g)₁ respectively. What is the relation among them ?

Which of the following statements are correct?
(A) The resistivity of a semiconductor decreases with increasing temperature.
(B) The potentiometer is unaffected by the internal resistance of the source.
(C) In ionic crystals and electrolytic liquids electrons carry the electric current.
(D) Ohm's law fails if V depends on I non-linearly.
(E) Kirchhoff's rules are used for analysis of electric circuits.
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Two charges 5 µC and -2 µC (with no external field) are placed at (-9 cm, 0, 0) and (9 cm, 0, 0) respectively. The work required to separate the two charges infinitely away from each other is :

A parallel beam of monochromatic light of wavelength 460 nm passes through a long slit of width 0.1 mm. What is the angular divergence in which most of the light is diffracted?

The graph showing correct variation of photo current with intensity of incident light:

C.V. Raman got Nobel Prize in 1930 for his discovery of:

Which of the following statements are correct for a transistor action ?
(A) The input resistance depends upon the current I_C in the transistor
(B) Collector currents is equal to the sum of base current and emitter current
(C) The emitter junction is forward biased
(D) The collector junction is reverse biased
(E) Both the emitter junction as well as the collector junction are forward biased
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One light year is equals to______.

Who among the following in Ancient India made some prominent discoveries in Physics?

The correct mathematical expression for amplitude modulated wave is:

The capacitance of capacitor increases when :
(A) its charge increases
(B) its supply voltage decreases
(C) common area of the plates increases
(D) separation between the plates decreases
Choose the correct answer

Let us consider interference between two sources of intensities I and 4I. What will be the intensity at points where the phase difference is π?

An infinite line charge produces an electric field of 9 × 10⁶ N/C at a distance of 20 cm. The linear charge density will be :

Energy band gap is maximum in:

For a medium with permittivity (e) and permeability (µ), the speed of light (v) is given by:

At what speed should a galaxy move with respect to earth so that spectral line of 600.0 nm appears as 600.6 nm?

Two polaroid P₁ and P₃ are placed such that their pass-axis are mutually perpendicular. Another polaroid P₂ is rotated between P₁ and P₃. For what angle θ between P₁ and P₂ the intensity of light emerging from P₃ will be maximum?

Match LIST I with LIST II

LIST I Device		LIST II  Purpose
A	Microphone	I	Used in vehicles to measure distance
B	Audiometer	II	For measuring the force and velocity of wind
C	Odometer	III	Converts sound waves to electrical vibrations
D	Anemometer	IV	Measures intensity of sound

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Match List I with List II

List-I		List-II
(A)	To slow down fast moving neutrons	(I)	Thermal neutrons
(B)	A neutron or a proton	(II)	Fission
(C)	Slow neutrons	(III)	Moderator
(D)	Neutron induced nuclear reaction	(IV)	Nucleon

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Consider two different hydrogen atoms. The electron in each atom is in first excited state. According to Bohr's model, electrons will have:

The logic gate realised using p-n junction diodes in the given figure is:

Which of the following is/are responsible for the formation of Rainbow?
(A) Dispersion of light
(B) Interference of light
(C) Reflection of light
(D) Refraction of light
Choose the correct answer from the options given below: