List of top Physics Questions

In Bohr?s model, the atomic radius of the first orbit is $r_0$ . The radius of the third orbit, is
In achromatic combination of lenses is formed by joining :
A machine gun fires a bullet of mass 40 g with a velocity 1200 $ms^{-1}$. The man holding it can exert a maximum force of 144 N on the gun. How many bullets can he fire per second at the most ?
A light ray is incident perpendicular to one face of a $90^{\circ}$ prism and is totally internally reflected at the glass-air interface. If the angle of reflection is $45^{\circ}$, we conclude that the refractive index $n$
For a given angle of projection, if the time of flight of a projectile is doubled, the horizontal range will increase to :
A fire screen produces sensation of cooling as :
If the pressure of a gas contained in a vessel is increased by $0.4\%$ when heated through $1^{\circ}C$, the initial temperature had been :
A concave mirror of focal length $15 \,cm$ forms an image having twice the linear dimension of the object. The position of the object when die image is virtual will be :
The velocity of bullet is reduced from $200\, m / s$ to $100 \,m / s$ while travelling through a wooden block of thickness of $10 \,cm$. The retardation assuming to be uniform, will be :
A fireman wants to slide down a rope. The breaking load for the rope is $\frac{3}{4}$th of the weight of the man. With what acceleration should the fireman slide down? (Acceleration due to gravity is g)
A current $i$ ampere flows along an infinitely long straight thin walled tube, then the magnetic induction at any point inside the tube is
A coil having n turns and resistance $4R\, O$. This combination is moved in time t seconds from a magnetic field $W_1$ weber to $W_2$ weber. The induced current in the circuit is
A streched string vibrates with a fundamental frequency of $200$ Hz. If its mass per unit length were to be doubled. What would be the frequency of the first harmonic ?
The intensity of sound from a radio at a distance of $2$ meters from its speaker is $1 \times 10^{-2} \mu W/m^2$. The intensity at a distance of $10$ meters would be
Light can be polarized because it
Light can be polarized by
An object travels $10$ km at a speed of $100$ m/sec and another $10$ km at $50$ m/sec. The average speed over the whole distance is
The time period of a simple pendulum is to be doubled. Its length should be
A concave lens and a convex lens have same focal length of $20$ cm and both put in contact with combination is used to view an object $5$ cm long kept at $20$ cm from the lens combination. As compared to object the image will be.
Longitudinal waves cannot show the phenomenon of
If two soap bubbles of different radii are connected by a tube,
One mole of ideal monoatomic gas $(\gamma = 5/3)$ is mixed with one mole of diatomic gas $(\gamma = 7/5)$. What is $\gamma$ for the mixture? $\gamma$ Denotes the ratio of specific heat at constant pressure, to that at constant volume.
Two masses $m_1 = 5$ kg and $m_2 = 4.8$ kg tied to a string are hanging over a light frictionless pulley. What is the acceleration of the masses when lift free to move? $(g = 9.8 m/s^2)$
Spherical balls of radius $'R'$ are falling in a viscous fluid of viscosity '$\eta$' with a velocity '$v$'. The retarding viscous force acting on the spherical ball is
A particle is acted upon by a force of constant magnitude which is always perpendicular to the velocity of the particle, the motion of the particle takes place in a plane. It follows that