List of top Physics Questions

If the terminal speed of a sphere of gold (density $= 19.5 kg/m^3$) is $0.2\, m/s$ in a viscous liquid (density $= 1.5\, kg/m^3$), find the terminal speed of a sphere of silver (density $= 10.5\, kg/m^3$) of the same size in the same liquid.

If $ \sigma $ = surface charge density, $ \varepsilon $ = electric permittivity the dimensions of $ \frac{ \sigma}{ \varepsilon } $ are same as

If L is the coherence length and c the velocity of light, the coherent time is

If a ray of light is incident on an equilateral glass prism PQR placed on a horizontal table, then for the minimum deviation which of the following is true?

Given below is a circuit diagram of an $AM$ demodulator.

For good demodulation of $AM$ signal of carrier frequency $f$, the value of $R C$ should be :

For a wire of length $l$ , maximum change in length under stress condition is $2 \,mm$. What is the charge in length under same conditions when length of wire is halved?

Flash light equipped with a new set of batteries, produces bright white light. As the batteries wear out,

Distance between successive compression and rarefaction is $1 \,m$ and velocity of sound is $360 \,ms^{-1}$. Find frequency :

Consider a two particle system with particles having masses $m_1$ and $m_2$. If the first particle is pushed towards the centre of mass through a distance $d$, by what distance should the second particle be moved, so as to keep the centre of mass at the same position ?

By sucking through a straw, a student can reduce the pressure in his lungs to $750\, mm$ of $Hg$ (density $= 13.6\, g/cm^3$ ). Using the straw, he can drink water from a glass upto a maximum depth of

In optical fibre, the diameter of the core is kept small. This smaller diameter of the core ensures that the fibre should have incident angle more than the critical angle required for total internal reflection.

Cobalt-$60$ is useful in cancer therapy Cobalt-$60$ is a source of $\gamma$-radiations capable of killing cancerous cells.

A thin stainless steel needle can lay floating on a still water surface. Any object floats when the buoyancy force balances the weight of the object.

Acceleration due to gravity at earth's surface is $g \,ms ^{-2}$. Find the effective value of gravity at a height of $32\, km$ from sea level $:\left(R_{e}=6400 \,km \right)$

Near earths surface, time period of a satellite is $4 h$. Find its time period at height $4R$ from the centre of earth :

A body of mass $0.1\, kg$ attains a velocity of $ 10\,ms^{-1}$ in $0.1 \,s.$ The force acting on the body is :

If force $\vec{ F }= 5 \hat{ i }+3 \hat{ j }+4 \hat{ k }$ makes a displacement of $\vec{ s }=6 \hat{ i }-5 \hat{ k }$, work done by the force is :

A body is moving in a circular path with acceleration $a$. If its velocity gets doubled, find the ratio of acceleration after and before the change :

A ball is thrown from height $h$ and another from $ 2h $ The ratio of time taken by the two balls to reach ground is:

A ball is thrown upwards, it takes $4 s$ to reach back to the ground. Find its initial velocity :

Interference was observed in an interference chamber when air was present. Now, the chamber is evacuated and if the same light is used, a careful observation will show:

$300\, J$ of work is done in sliding a $2 kg$ block up an inclined plane of height $10 \,m$. Taking $g=10\, m / s ^{2}$, work done against friction is :

Aerofils are so designed that the speed of air:

The magnetic moment has dimensions of:

$27$ small drops each having charge $q$ and radius $r$ coalesce to from big drop. How many times charge and capacitance will become?