List of top Physics Questions

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

Mobility of free electrons in a conductor 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

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

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

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?

Two thin circular discs of mass $m$ and $4\, m$, having radii of $a$ and $2 a$, respectively, are rigidly fixed by a massless, rigid rod of length $l=\sqrt{24}$ a through their centers. This assembly is laid on a firm and flat surface and set rolling without slipping on the surface so that the angular speed about the axis of the rod is $\omega$. The angular momentum of the entire assembly about the point 'O' is $\vec{ L }$ (see the figure). Which of the following statement(s) is(are) true?

A conducting loop in the shape of a right angled isosceles triangle of height $10\, cm$ is kept such that the $90^{\circ}$ vertex is very close to an infinity long conducting wire (see the figure). The wire is electrically insulated from the loop. The hypotenuse of the triangle is parallel to the wire. The current in the triangular loop is in counterclockwise direction and increased at a constant rate of $10 \,As ^{-1}$. Which of the following statement (s) is (are) true?

The ends $Q$ and $R$ of two thin wires, $PQ$ and $RS$, are soldered (joined) together. Initially each of the wires has a length of $1\, m$ at $10^{\circ} C$. Now the end $P$ is maintained at $10^{\circ} C$, while the end $S$ is heated and maintained at $400^{\circ} C$. The system is thermally insulated from its surroundings. If the thermal conductivity of wire $PQ$ is twice that of the wire RS and the coefficient of linear thermal expansion of $PQ$ is $1.2 \times 10^{-5} K ^{-1}$, the change in length of the wire $PQ$ is