List of top Physics Questions

Find the value of current \(I\) in the circuit shown in the figure below.

The current-voltage graphs for a given conducting sample at two different temperatures \(T_1\) and \(T_2\) are shown in the figure below. \(R_1\) is the resistance of the sample at temperature \(T_1\) and \(R_2\) is the resistance at temperature \(T_2\). Choose the correct answer.

A battery is kept connected to the plates of a parallel-plate capacitor. A dielectric slab of dielectric constant \(K\) is then introduced between the plates such that it covers the entire space between the plates. Choose the correct answer from the given alternatives.

A hollow metal sphere of radius \(r\) contains a charge \(+Q\). Consider an imaginary circle of radius \(R\,(R\gt r)\) concentric with the charged sphere. A point charge \(q\) is carried from (I) \(A\) to \(B\) and then from (II) \(A\) to \(C\). Choose the correct answer from the given alternatives.

A particle accelerates from rest at constant rate \[ \alpha=6\ \text{m s}^{-2} \] for some time, after which it decelerates at constant rate \[ \beta=4\ \text{m s}^{-2} \] to come to rest. If the total time of travel is \(10\) seconds, what is the maximum speed attained by the particle during its motion?

Three small particles \(A\), \(B\) and \(C\) of equal mass move with equal speed \(v\) along the medians of an equilateral triangle as shown. They collide at the centroid \(G\) of the triangle. After the collision, \(A\) comes to rest, while \(B\) retraces its path with the same speed \(v\). What is the speed and direction of motion of \(C\) after the collision?

Two spheres of the same material have radii \(1\,m\) and \(2\,m\), and temperatures \(2000\,K\) and \(1000\,K\) respectively. What is the ratio of energy radiated per second by the first sphere to that by the second?

In the circuit shown below, determine the current in the resistor. Given: \[ E=10.7\ \text{V} \] \[ R=10\,k\Omega \] Silicon diode in forward bias.

Which of the following semiconductors is electrically negative?

Five point charges, each of value \(+q\), are placed on five vertices of a regular hexagon of side \(L\). What is the magnitude of the force on a point charge \(-q\) placed at the centre of the hexagon?

A solenoid of resistance \(40\,\Omega\) and inductance \(80\,H\) is connected to a \(200\,V\) battery. How long will it take the current to reach \(50\%\) of its final equilibrium value?

Two parallel wires \(AL\) and \(BM\), placed at a distance \(l\), are connected by a resistor \(R\) and placed in a magnetic field \(B\) perpendicular to the plane of the wires. Another wire \(CD\) connects the two wires perpendicularly and is made to slide with velocity \(v\). Neglect the resistance of all the wires. What is the work done per second needed to slide the wire \(CD\)?

A proton has a velocity \[ \vec v=3\hat i+4\hat j\ \text{m s}^{-1} \] and is subjected to a magnetic field \[ \vec B=5\hat k\ \text{T}. \] Then

For a given length \(L\) of a wire carrying a current \(I\), how many circular turns will produce the maximum magnetic moment?

How many grams of ice at \(-20^\circ\mathrm{C}\) will be needed to cool \(1.1\) litres of water from \(30^\circ\mathrm{C}\) to \(20^\circ\mathrm{C}\)? \[ c_{\text{ice}}=0.5\ \text{cal g}^{-1}\,{}^{\circ}\mathrm{C}^{-1} \] \[ L_f=80\ \text{cal g}^{-1} \]

In a steel plate of length \(100\) cm and breadth \(50\) cm, there is a hole in the shape of an equilateral triangle of side \(10\) cm. The coefficient of linear expansion of steel is \(1.2\times10^{-5}\,{}^{\circ}\mathrm{C}^{-1}\). The temperature of the steel plate is increased by \(100^\circ\mathrm{C}\). What will be the percentage change in the area of the triangular hole?

A wave represented by the equation \[ y=a\cos(kx-\omega t) \] is superposed with another to form a stationary wave such that point \(x=0\) is a node. What is the equation for the other wave?

Find the de Broglie wavelength associated with a thermal neutron of mass \(m\) at absolute temperature \(T\). \[ k=\text{Boltzmann constant}, \qquad h=\text{Planck's constant} \]

The work done in turning a magnetic dipole of magnetic moment \(M\) in a magnetic field \(B\) by an angle \(90^\circ\) from the meridian is \(n\) times the corresponding work done in turning it through an angle of \(60^\circ\) in the same field and from the same initial condition. Find the value of \(n\).

The fundamental frequency of a sonometer wire increases by \(4\) Hz if the tension in the string is increased by \(21\%\) keeping the length of the wire constant. What will be the new fundamental frequency of the wire if its length is increased by \(25\%\) while keeping the original tension in the wire?

Two wires \(W_1\) and \(W_2\) of the same material and equal radius are stretched by equal forces well within their elastic limit. If the lengths of wires \(W_1\) and \(W_2\) are in the ratio \(1:3\), then what will be the ratio of strains produced in wires \(W_1\) and \(W_2\)?

A particle is executing a simple harmonic motion with time period \(T\) and amplitude \(A\) and having the origin at \(O\). What is the time difference between its travel from \(O\) to \(A/2\) and from \(A/2\) to \(A\) on one side of the origin?

Find the energy released, if \(5\) g of \(^{235}\mathrm{U}\) is completely consumed in a chain reaction.

The mean lives of a radioactive substance are \(1620\) years and \(405\) years for \(\alpha\)-emission and \(\beta\)-emission respectively. Find the time during which three-fourths of a sample will decay if it is decaying by both \(\alpha\)-emission and \(\beta\)-emission simultaneously.

A \(\mu\)-meson of charge equal to that of an electron \((-e)\) and mass \(208\) times the mass of an electron moves in a circular orbit around a nucleus of charge \(+3e\). Assuming that the Bohr model is applicable and the mass of the nucleus is infinite, find the orbit number \(n\) for which the radius of the orbit is approximately the same as that of the first Bohr orbit of hydrogen atom.