List of top Physics Questions

Ten resistors, each having resistance of $6\text{ }\Omega$, are connected in a circuit. Then the ratio of maximum current to the minimum current that can flow through the circuit is:
The half-life of a radioactive substance is 20 minutes. $\frac{1}{3}$rd part of substance has decayed in time $t_1$ and $\frac{2}{3}$rd part of it has decayed in time $t_2$. Then, ($t_2 - t_1$) is nearly
A particle is moving along a straight line such that its velocity is increasing at $5\text{ ms}^{-1}$ per meter. When its velocity becomes $20\text{ ms}^{-1}$ its acceleration is:
An object placed in front of a concave mirror at a distance of $x\text{ cm}$ from the pole gives a 3 times magnified real image. If it is moved to a distance of $(x + 5)\text{ cm}$, the magnification of the image becomes 2. The focal length of the mirror is:
A cyclist moves in such a way that he takes $72^\circ$ turn towards left after travelling $200\text{ m}$ in a straight line. His displacement when he just takes fourth turn like that is:
Magnetic field at $0.1\text{ m}$ from a long straight wire carrying $10\text{ A}$ current is:
A wire of length $1\text{ m}$ is broken into two unequal parts $P$ and $Q$. Part $P$ is extended to double its length so that its resistance become equal to resistance of $Q$. The length of $Q$ part is:
An amplitude modulated wave is represented by $C_m(t) = 30 \sin 300\pi t + 10(\cos 200\pi t - \cos 400\pi t)$. Then the carrier wave frequency, signal frequency and modulation index are respectively
The pressure \(P_1\) and density \(d_1\) of a diatomic gas change to \(P_2\) and \(d_2\) during an adiabatic operation. Find the value of \[ \frac{P_1}{P_2}, \] if \[ \frac{d_2}{d_1}=32. \]
The ratio of the turns per unit length in two inductors is \[ 2:1. \] Then the ratio of the impedances produced by the inductors is
A toroid of \(1000\) turns has average radius \[ \frac{\mu_0}{\pi}\ \text{metre}. \] If a current of \(1\,A\) is flowing through it, then the magnetic field intensity inside the coil of the toroid is
An electron has an angular momentum of \[ 90h\ \text{J s} \] while orbiting with a linear velocity of \[ \pi\times10^5\ \text{m s}^{-1}. \] Then the radius of the orbit is \[ \left( m_e=9\times10^{-31}\,\text{kg}, \quad h=6.6\times10^{-34}\,\text{J s} \right) \]
216 identical spherical drops each having a positive charge of \[ 10\,\text{nC} \] combine to form a big spherical drop. If the radius of each small drop is \[ 3\,\text{mm}, \] then the capacitance and electric potential of the big drop are respectively
The moment of inertia of a rod about an axis passing through its centre and perpendicular to its length is \[ I=\frac{1}{12}ML^2, \] where \(M\) is the mass and \(L\) is the length of the rod. The rod is bent in the middle so that the two halves make an angle of \(60^\circ\). The moment of inertia of the bent rod about the same axis would be
A light of energy flux \[ 9\ \text{W cm}^{-2} \] is incident for \(20\) minutes on a black surface of area \[ 100\ \text{cm}^2. \] Then the maximum average force exerted on the surface is \[ (c=3\times10^8\ \text{m s}^{-1}) \]
A cricketer can throw a ball with a speed of \(V_0\). If he throws the ball while running with a speed \(V_0\), at an angle \(\alpha\) with the horizontal, then the range of the ball will be maximum when \(\alpha\) is
An artificial satellite of mass \(m\) revolves around a planet in a circular orbit of radius \(R\) under the influence of an attractive central force given by \[ F\propto R^{-5/2}. \] How do the orbital velocity \(V\) and time period \(T\) depend on the orbital radius \(R\)?
The value of \(Q\) in the given digital circuit is
An inductor of inductance \[ 5\,\text{H} \] is carrying an electric current of \[ 4\,\text{mA}. \] Then the energy stored in the inductor is
Match the law/principle with the concerned application: \[ \begin{array}{|c|c|} \hline \textbf{Application} & \textbf{Law / Principle} \\ \hline a)\ \text{Hydraulic Lift} & i)\ \text{Bernoulli's Principle} \\ \hline b)\ \text{Speed of Efflux} & ii)\ \text{Torricelli's Law} \\ \hline c)\ \text{Dynamic Lift} & iii)\ \text{Stoke's Law} \\ \hline d)\ \text{Viscous Drag Force} & iv)\ \text{Pascal's Law} \\ \hline \end{array} \]
The type of radioactive decay that involves the emission of a positron is
When a uniform bar of length \(l\), breadth \(b\) and thickness \(d\) is supported by rigid supports near the ends and loaded at the centre by a vehicle of mass \(M\), the bar sags by an amount \(\delta\). If \(Y\) is the Young's modulus of the material, then \(\delta\) is
Which of the following graphs is correctly drawn between temperature \((t)\) and density \((d)\) of water?
The blades of a windmill sweep out a circle of area \[ A=2\,\text{m}^2. \] The wind is flowing with velocity \[ V=6\,\text{ms}^{-1} \] perpendicular to the circle and the density of air is \[ \rho=1.2\,\text{kgm}^{-3}. \] Then the power of the mill is
A solid sphere of mass \(2\,\text{kg}\) is at rest inside a cube as shown in the figure. The cube moves with velocity \[ \vec v=(5t\,\hat i+2t\,\hat j)\,\text{ms}^{-1}, \] where \(t\) is time in seconds. If the sphere is at rest with respect to the cube, find the force exerted by the sphere on the cube. (All surfaces are smooth and \(g=10\,\text{ms}^{-2}\)).