List of top Physics Questions

A length-scale $(\ell)$ depends on the permittivity $(\varepsilon)$ of a dielectric material, Boltzmann constant $\left( k _{ B }\right)$, the absolute temperature $(T)$, the number per unit volume $(n)$ of certain charged particles, and the charge $(q)$ carried by each of the particles. Which of the following expressions (s) for $\ell$ is (are) dimensionally correct?

Three particles $ P, Q $ and $ R $ are at rest at the vertices of an equilateral triangle of side $ s $ . Each of the particles starts moving with constant speed $ v \,ms^{-1}. P $ is moving along $ PQ, Q $ along $ QR $ and $ R $ along $ RP $ . The particles will meet each other at time $ t $ given by

Mobility of free electrons in a conductor is

In the following network potential at $'O'$

Variation of resistance of the conductor with temperature is as shown .The temperature co-efficient $(\alpha)$ of the conductor is

A 220 volt - 1000 watt bulb is connected across a 110 volt mains supply. The power consumed will be

Three resistances $P, Q, R$ each of $2\, \Omega$ and an unknown resistance $S$ form the four arms of a Wheatstone bridge circuit. When a resistance of $6\, \Omega$ is connected in parallel to $S$ the bridge gets balanced. What is the value of $S$ ?

In a potentiometer, auniform potential gradient of $ 0.8 \,V \,m^{-1} $ is maintained across its $ 10 \,m $ wire. The potential difference across two points on the wire located at $ 0 \,m \,65\, cm $ and $ 2 \,m\, 45 \,cm $ is

A particle executing $SHM $ has a maximum speed of $0.5 \, ms^{ -1}$ and maximum acceleration of $1.0 \, ms^{-2}$ The angular frequency of oscillation is

A cylinder of radius $R$, length $L$ and density $\rho$ floats upright in a fluid of density $\rho_0$. If it is given a small downward displacement of amplitude $x$, the time period of resulting undamped oscillation is

Time period of pendulum, on a satellite orbiting the earth, is

Two pith balls, each of mass 1.8 g are suspended from the same point by silk threads each of length 20 cm. When equal charge $Q$ is given to both the balls, they separate until the two threads become perpendicular. Then the charge $Q$ on each pith ball is $\left[\frac{1}{4\pi \varepsilon_0 }=9 \times10^{9} N m^{2} C^{-2}\right]$

A charge $Q$ is to be divided into two parts : $q$ and $Q - q$. What is the relation between $q$ and $Q$ if the two parts, when placed apart, has maximum coloumb repulsion

Three concentric metallic spherical shells of radii $R, 2R$ and $3R$ are given charges $Q_1, Q_2, Q_3$ respectively. It is found that the surface charge densities on the outer surface of the shells are equal. Then the ratio of the charges given to the shells $Q_1 : Q_2 : Q_3$ is

A charge $+q$ is placed at origin. There are two concentric spherical surfaces; $S_1$ of radius $R$ and $S_2$ of radius $2R$. Both the surfaces have their centres at the origin. Let $\phi_1$ denote the flux through $S_1$ and $\phi_2$ the flux through $S_2$. The relation between $\phi_1$ and $\phi_2$ is

The correct statement about electric dipole is

Three identical charges are placed at the vertices of an equilateral triangle. The force experienced by each charge, (if k = 1/4$\pi\varepsilon_{0}$) is

An electron initially at rest, is accelerated through a potential difference of 200 volt, so that it acquires a velocity ${8.4 \times 10^6 m s^{-1}}$, the value of $e/m$ of electron will be

In water, value of magnetic field decreases. Water is a diamagnetic substance.

Figure shows the total acceleration $a = 32m/s^2$ of a moving particle moving clockwise in a circle of radius $R=1m$. What are the centripetal acceleration and speed $v$ of the particle at given instant?

A projectile is projected with an initial velocity $\left(4\hat{i}+5\hat{j}\right)m/s$. Here $\hat{j}$ is the unit vector directed vertically upwards and unit vector $\hat{i}$ is in the horizontal direction .Velocity of the projectile (in $m/s$) just before it hits the ground is

The process of superimposing message signal on high frequency carrier wave is called

A long solenoid with $40$ turns per cm carries a current of $1\,A$. The magnetic energy stored per unit volume is ........ $J/ m^3$.

Consider two identical galvanometers and two identical resistors with resistance $R$. If the internal resistance of the galvanometers $R _{ C }< R / 2$, which of the following statement(s) about any one of the galvanometers is(are) true?

A transparent slab of thickness $d$ has a refractive index $n(z)$ that increases with $z$. Here $z$ is the vertical distance inside the slab, measured from the top. The slab is placed between two media with uniform refractive indices $n _{1}$ and $n _{2}\left(> n _{1}\right)$, as shown in the figure. A ray of light is incident with angle $\theta_{i}$ from medium $1$ and emerges in medium $2$ with refraction angle $\theta_{f}$ with a lateral displacement $l .$ Which of the following statement(s) is(are) true?