List of top Physics Questions

The ratio of vapour densities of two gases at the same temperature is \( \frac{4}{25} \), then the ratio of r.m.s. velocities will be:

In a resonance tube closed at one end. Resonance is obtained at lengths \( l_1 = 120 \, \text{cm} \) and \( l_2 = 200 \, \text{cm} \). If \( v_s = 340 \, \text{m/s} \), find the frequency of sound.

Consider a circular loop that is uniformly charged and has a radius $ \sqrt{2} $. Find the position along the positive $ z $-axis of the cartesian coordinate system where the electric field is maximum if the ring was assumed to be placed in the $ xy $-plane at the origin:

Match the LIST-I with LIST-II

LIST-ILIST-II
A.Boltzmann constantI.\( \text{ML}^2\text{T}^{-1} \)
B.Coefficient of viscosityII.\( \text{MLT}^{-3}\text{K}^{-1} \)
C.Planck's constantIII.\( \text{ML}^2\text{T}^{-2}\text{K}^{-1} \)
D.Thermal conductivityIV.\( \text{ML}^{-1}\text{T}^{-1} \)

Choose the correct answer from the options given below :

Mean free path for an ideal gas is observed to be 20 μm while the average speed of molecules of gas is observed to be 600 m/s, then the frequency of collision is near?
A galvanometer having a coil of resistance 30 \( \Omega \) needs 20 mA of current for full-scale deflection. If a maximum current of 3 A is to be measured using this galvanometer, the resistance of the shunt to be added to the galvanometer should be \( X \, \Omega \), where \( X \) is:
A sinusoidal wave of wavelength 7.5 cm travels a distance of 1.2 cm along the x-direction in 0.3 sec. The crest P is at $ x = 0 $ at $ t = 0 $ sec and maximum displacement of the wave is 2 cm. Which equation correctly represents this wave?
The equation of a transverse wave travelling along a string is \( y(x, t) = 4.0 \sin \left( 20 \times 10^{-3} x + 600t \right) \) mm, where \( x \) is in mm and \( t \) is in seconds. The velocity of the wave is:
A coil of resistance 10 \( \Omega \) is connected to a battery of 12 V. If the current flowing through the coil is 2 A, what is the power dissipated in the coil?
A proton and an \( \alpha \)-particle are accelerated by the same potential difference. Find out the ratio of their de Broglie wavelengths.
Two water drops each of radius \( r \) coalesce to form a bigger drop. If \( T \) is the surface tension, the surface energy released in this process is:
An electric bulb rated as 100 W-220 V is connected to an ac source of rms voltage 220 V. The peak value of current through the bulb is :
A proton enters a uniform magnetic field $\vec{B} = 0.5 \hat{k} \ \text{T}$ with velocity $\vec{v} = 10^6 \hat{i} \ \text{m/s}$. The magnitude of the magnetic force on the proton is:
At what temperature the surface tension of a liquid becomes zero?
The power rating of a ceiling fan rotating with a constant torque of 2 Nm with an angular speed of 2\(\pi\) rad/s will be ............
"If two systems are each in thermal equilibrium with a third system, they are also in thermal equilibrium with each other." This statement refers to :
A charge \( Q \) is fixed in position. Another charge \( q \) is brought near charge \( Q \) and released from rest. Which of the following graphs is the correct representation of the acceleration of the charge \( q \) as a function of its distance \( r \) from charge \( Q \)?
In an n-type semiconductor, electron-hole combination is a continuous process at room temperature. Yet the electron concentration is always greater than the hole concentration in it. Explain.
Given below are two statements. One is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A): Refractive index of glass is more than air.
Reason (R): Optical density of a medium is directly related to its mass density.
In the light of the above statements, choose the correct answer from the options given below.

The graph shows the variation of current with voltage for a p-n junction diode. Estimate the dynamic resistance of the diode at \( V = -0.6 \) V. 

voltage for a p-n junction diode
A convex lens has a focal length of 10 cm. What is the magnification produced when the object is placed 30 cm from the lens?
A ray of light is incident at an angle \( i \) on a parallel sided glass slab of thickness \( d \) and gets refracted into the slab at angle \( r \). Draw a ray diagram to show its path as it emerges out of the slab. Hence, obtain an expression for the lateral shift of the ray. Under what condition will the shift be minimum?
The inward electric flux through a closed surface is \( 6 \times 10^{-5} \) and the outward flux is \( 3 \times 10^{-5} \). Then the total charge enclosed is?
Using Newton's law of viscosity for streamline flow, derive an expression for coefficient of viscosity.
A car of mass 800 kg is moving in a circular path with a radius of 50 m at a speed of 20 m/s. Calculate the centripetal force acting on the car.