List of top Physics Questions

A transverse wave is represented by : $y = \frac{10}{\pi} \sin \left(\frac{2\pi}{T}t-\frac{2\pi}{\lambda}x\right)$ For what value of the wavelength the wave velocity is twice the maximum particle velocity ?

The total length of a sonometer wire between fixed ends is $110\, cm$. Two bridges are placed to divide the length of wire in ratio $6 : 3 : 2$. The tension in the wire is $400\, N$ and the mass per unit length is $0.01\, kg/m$. What is the minimum common frequency with which three parts can vibrate ?

A thin bar of length $L$ has a mass per unit length $\lambda$, that increases linearly with distance from one end. If its total mass is $M$ and its mass per unit length at the lighter end is $\lambda_{0}$, then the distance of the centre of mass from the lighter end is :

A bullet looses $\left(\frac{1}{n}\right)^{th}$ of its velocity passing through one plank. The number of such planks that are required to stop the bullet can be :

When a rubber -band is stretched by a distance x, it exerts a restoring force of magnitude $ F = ax + bx^2$, where a and b are constants. The work done in stretching the unstretched rubber-band by $L$ is :

Consider a cylinder of mass $M$ resting on a rough horizontal rug that is pulled out from under it with acceleration $'a'$ perpendicular to the axis of cylinder. What is $F_{friction}$ at point $P$ ? It is assumed that the cylinder does not slip.

A particle is released on a vertical smooth semicircular track from point $X$ so that $OX$ makes angle $\theta$ from the vertical (see figure). The normal reaction of the track on the particle vanishes at point $Y$ where $OY$ makes angle $\phi$ with the horizontal. Then :

A body of mass $5\, kg$ under the action of constant force $\vec{F}=F_{x} \hat{i} +F_{y} \hat{j}$ has velocity at $t = 0\,s$ as $\vec{\upsilon} = \left(6\hat{i} - 2\hat{j}\right)$ m/s and at $t = 10 s$ as $\vec{\upsilon}=+6 \hat{j}$ m/s. The force $\vec{F}$ is :

A block of mass m is placed on a surface with a vertical cross-section given by $y = \frac{x^3}{6}$ If the coefficient of friction is $0.5$, the maximum height above the ground at which the block can be placed without slipping is

A square frame of side 10 cm and a long straight wire carrying current 1 A are in the plane of the paper. Starting from close to the wire, the frame moves towards the right with a constant speed of 10 ms (see figure). The e.m.f induced at the time the left arm of the frame is at x = 10 cm from the wire is :

Assume that an electric field $\vec{E}=30 x^{2} \hat{i}$ exists in space. Then the potential difference $V_{A}-V_{O'}$ where $V_{O}$ is the potential at the origin and $V_{A}$ the potential at $x=2 \,m$ is

In a large building, there are 15 bulbs of 40\, W, 5 bulbs of 100 W, 5 fans of $80\, W$ and 1 heater of $1\, kW$. The voltage of the electric mains is $220 \,V$. The minimum capacity of the main fuse of the building will be :

In the circuit shown, current (in A) through the 50 V and 30 V batteries are, respectively :

The circuit shown here has two batteries of $8.0\, V$ and $16.0\, V$ and three resistors $3 \Omega , 9 \Omega$ and $9 \Omega$ and a capacitor $5.0 \mu F$.

How much is the current $I$ in the circuit in steady state ?

The surface tension and vapour pressure of water at $30^{\circ} C$ are $7.2 \times 10^{-2} N / m$ and $2.4 \times 10^{3}$, respectively. What is the radius of the smallest droplet of water which can be formed without evaporating at $30^{\circ} C$ ?

In terms of resistance $R$ and time $T$, the dimensions of ratio $\frac{\mu}{\epsilon}$ of the permeability ${\mu}$ and permittivity ${\epsilon}$ is :

A thin non-conducting rod of length $50 \,cm$ has a positive charge of uniform linear density $10^{-12} \,C / m$. Find the electric potential due to the rod at a point, which is at a perpendicular distance of $1.0 \,cm$ from one-end of the rod $\left(\varepsilon_{0}=8.8 \times 10^{-12} F / m \right)$.

An object is located in a fixed position in front of a screen. Sharp image is obtained on the screen for two positions of a thin lens separated by $10\, cm$. The size of the images in two situations are in the ratio 3 : 2. What is the distance between the screen and the object ?

During an adiabatic compression, $830\, J$ of work is done on $2$ moles of a diatomic ideal gas to reduce its volume by $50\%$. The change in its temperature is nearly : $(R = 8.3 JK^{-1}\, mol^{-1})$

A gas is compressed from a volume of $2 \,m^3$ to a volume of $1\, m^3$ at a constant pressure of $100\, N/m^2$. Then it is heated at constant volume by supplying $150\, J$ of energy. As a result, the internal energy of the gas :

An ideal monoatomic gas is confined in a cylinder by a spring loaded piston of cros section $8.0 \times 10^{-3} \, m^2$. Initially the gas is at 300K and occupies a volume of $2.4 \times 10^{-3} \, m^3$ and the spring is in its relaxed state as shown in figure. The gas is heated by a small heater until the piston moves out slowly by $0.1\, m$. The force constant of the spring is $8000\, N/m$ and the atmospheric pressure is $1.0 \times 10^5 \, N/m^2$. The cylinder and the piston are thermally insulated. The piston and the spring are massless and there is no friction between the piston and the cylinder. The final temperature of the gas will be : (Neglect the heat loss through the lead wires of the heater. The heat capacity of the heater coil is also negligible)

When the rms voltages $V _{ L }, V _{ C }$ and $V _{ R }$ are measured respectively across the inductor $L ,$ the capacitor $C$ and the resistor $R$ in a series LCR circuit connected to an AC source, it is found that the ratio $V _{ L }: V _{ C }: V _{ R }=1: 2: 3$. If the rms voltage of the AC sources is $100 \,V ,$ the $V _{ R }$ is close to:

A spherically symmetric charge distribution is characterised by a charge density having the following variation : $\rho\left(r\right)=\rho_{0}\left(1-\frac{r}{R}\right)$ for $r < R$ $\rho \left(r\right)=0 \,$ for $r\ge R$ Where $r$ is the distance from the centre of the charge distribution and $\rho_{0}$ is a constant. The electric field at an internal point $(r < R)$ is

A d.c. main supply of e.m.f. $220\, V$ is connected across a storage battery of e.m.f. $200\, V$ through a resistance of $1$ $\Omega$. The battery terminals are connected to an external resistance '$R$'. The minimum value of '$R$', so that a current passes through the battery to charge it is :

A person is driving a vehicle at uniform speed of $5\, ms ^{-1}$ on a level curved track of radius $5\, m .$ The coefficient of static friction between tyres and road is $0.1 .$ Will the person slip while taking the turn with the same speed ? Take $g =10\, ms ^{-2}$ Choose the correct statement.