List of top Physics Questions

A plane square sheet of charge of side $0.5\, m$ has uniform surface charge density. An electron at $1\, cm$ from the centre of the sheet experiences a force of $1.6 \times 10^{-12}\, N$ directed away from the sheet. The total charge on the plane square sheet is $\left(\varepsilon_{0}=8.854 \times 10^{-12} C ^{2} m ^{-2}\, N ^{-1}\right)$
A convergent beam is incident on a convex lens. What will be the nature of the image formed ?
If the velocity of a charged particle has the component both in and perpendicular to the direction of the magnetic field then the path traced by the charged particle will be?
A circular disc is rotating about its own axis at uniform angular velocity \(\omega.\) The disc is subjected to uniform angular retardation by which its angular velocity is decreased to \(\frac {\omega}{2}\) during 120 rotations. The number of rotations further made by it before coming to rest is
The least count of a stop watch is $0.2\, s$. The time of $20$ oscillations of a pendulum is measured to be $25\, s$. The percentage error in the time period is
Two pendulums of lengths 100 cm and 121 cm start vibrating. At some instant the two are at the mean position in the same phase. After how many vibrations of the longer pendulum will the two be in the sam phase at the mean position again?
Match List I with List II:
List IList II
(A) AM Broadcast(I) 88 – 108 MHz
(B) FM Broadcast(II) 540 – 1600 KHz
(C) Television(III) 3.7 – 4.2 GHz
(D) Satellite Communication(IV) 54 – 890 MHz
Choose the correct answer from the options given below:

A photon is emitted in transition from \( n = 4 \) to \( n = 1 \) level in a hydrogen atom. The corresponding wavelength for this transition is:

The effect of rotation of the Earth on the value of acceleration due to gravity is
In a grid iron pendulum , there are 3 iron rods and 4 brass rods , Length of each brass rod is 50 cm . $\alpha $ of iron is $12 \times 10^{-6} \,/^{\circ} C$ and $\alpha $ of brass is $18 \times 10^{-6}\,/^{\circ} C$ . Length of each iron rod is
The unit of self-inductance is
$100\,g$ of ice is mixed with $100\,g$ of water at $100^\circ\,C$. What will be the final temperature of the mixture
A boy of mass 50 kg is standing at one end of a, boat of length 9 m and mass 400 kg. He runs to the other, end. The distance through which the centre of mass of the boat boy system moves is
A vessel, whose bottom has round holes with diameter $0.1\, m\, m$, is filled with water. The maximum height up to which water can be filled without leakage is (Surface tension of water $= 75$ dyne $cm^{-1}$ and $g = 1000\, cm\,s^{-2}$)
The centre of mass of a system of three particles of masses $1g, 2g$ and $3g$ is taken as the origin of a coordinate system. The position vector of a fourth particle of mass $4 g$ such that the centre of mass of the four particle system lies at the point $(1, 2, 3)$ is a $(\hat i + 2 \hat j + 3 \hat k)$ , where a is a constant. The value of $\alpha$ is
A capillary tube of radius r is dipped inside a large vessel of water. The mass of water raised above water level is M. If the radius of capillary is doubled, the mass of water inside capillary will be
The electrical resistance of a conductor depends upon
A series LCR circuit with R = 20 W, L = 1.5 H and C = 35 μF is connected to a variable-frequency 200 V ac supply. When the frequency of the supply equals the natural frequency of the circuit, what is the average power transferred to the circuit in one complete cycle?
The numerical ratio of displacement to the distance covered is always:
A magnetic field exerts no force on :
A stationary wheel starts rotating about its own axis at an angular acceleration $5.5tad/s^2.$ To acquire an angular velocity 420 revolutions per minute, the number of rotations made by the wheel is
A test charge is moved from lower potential point to a higher potential point. The potential energy of test charge will
Two pulley arrangements (A) and (B) are as shown in the figure. Neglect the masses of the ropes and pulleys and the friction at the axle of the pulleys. The ratio of the acceleration of mass m in arrangement (A) to that in arrangement (B) is

A tank is filled with water to a height of 12.5cm. The apparent depth of a needle lying at the bottom of the tank is measured by a microscope to be 9.4cm. What is the refractive index of water? If water is replaced by a liquid of refractive index 1.63 up to the same height, by what distance would the microscope have to be moved to focus on the needle again?

Three masses $m,\, 2\, m$ and $3\, m$ are arranged in two triangular configurations as shown in figure $1$ and figure $2$ . Work done by an external agent in changing, the configuration from figure $1$ to figure $2$ is