List of top Physics Questions

A Carnot engine with efficiency 50% takes heat from a source at 600 K. To increase the efficiency by 20%, keeping temperature of the sink same, the new temperature of the source will be

One gram of a liquid is converted to vapour at \(3\times 10^5\) Pa pressure. If 10% of the heat supplied is used for increasing the volume by \(1600 \text{cm}^3\) during this phase change, then the increase in internal energy in the process will be

One thousand small water drops of equal radii combine to form a big drop. The ratio of final surface energy to the total initial surface energy is

Solid sphere is rotating about an axis as shown in figure. If the radius of the sphere is 5 cm, then radius of gyration about that axis will be \(\sqrt{x}\) cm. The value of x is

Under isothermal condition, two soap bubbles of radii \(r_1\) and \(r_2\) combine to form a single soap bubble of radius R. The surface tension of the soap solution is (P = outside pressure)

A body of mass m is taken from earth surface to a height h equal to twice the radius of earth, the increase in potential energy will be (\(g\) = acceleration due to gravity on earth's surface) (R - radius of earth)

A uniform solid cylinder with radius R and length L has moment of inertia \(I_1\) about the axis of the cylinder. A concentric solid cylinder of radius \(R/2\) and length \(L/2\) is carved out of the original cylinder. If \(I_2\) is the moment of inertia of the carved out portion of the cylinder then \(I_1/I_2\) is (Both \(I_1\) and \(I_2\) are about the axis of the cylinder)

A body of mass 1kg begins to move under the action of a time dependent force \(\overset{⃗}{F} = (t\hat{i}+3t^2\hat{j}) \text{N}\) where \(\hat{i}\) and \(\hat{j}\) are the unit vectors along x and y axis. The power developed by the above force at time \(t = 2 \text{s}\) will be (in watt)

The error in the measurement of length and mass of a cube is 3% and 4% respectively. The error in the measurement of its density will be

Two objects are projected with same velocity 'u' at different angles \(α\) and \(β\) with the horizontal. If \(α+β = 90^{\circ}\), the ratio of horizontal range of the first object to the second object will be \([sin(π-θ) = sinθ]\)

A solid sphere of mass M and a disc of mass \(\frac{M}{2}\) have the same radius. The ratio of moment of inertia of the disc about a tangent in its plane to the moment of inertia of the sphere about its tangent will be

Vectors \(a\hat{i}+b\hat{j}+\hat{k}\) and \(2\hat{i}-3\hat{j}+4\hat{k}\) are perpendicular to each other when \(3a+2b = 7\), the ratio of a to b is \(x/2\). The value of x is

The resultant gate and its Boolean expression in the given circuit is

When a small amount of impurity atoms are added to a semiconductor then generally its resistivity

Using Bohr's atomic model, the orbital period of electron in hydrogen atom in the \(n^{\text{th}}\) orbit is (\(ε_0\)=permittivity of free space, h=Planck's constant, m = mass of electron, e = electronic charge)

In a transistor amplifier, a change of 0.2 mA in the base current causes a change of 5 mA in the collector current. If input resistance is \(2 \text{k}\Omega\) and voltage gain is 75, the load resistance used in the circuit is

For a photosensitive material, work function is '\(W_0\)' and stopping potential is 'V'. The wavelength of the incident radiation is (h=Planck's constant, c = velocity of light, e = electronic charge)

The force acting on the electron in hydrogen atom (Bohr's theory) is related to the principal quantum number n as

In Young's double slit experiment, the distance between the slits is 3 mm and the slits are 2m away from the screen. Two interference patterns can be obtained on the screen due to light of wavelength 480 nm and 600 nm respectively. The separation on the screen between the \(5^{\text{th}}\) order bright fringes on two interference patterns is

In Young's double slit experiment, the fringe width is 0.4 mm. What is the distance between \(4^{\text{th}}\) dark band and \(6^{\text{th}}\) bright band on the same side of the interference pattern?

Using Einstein's photoelectric equation, the graphical representation between the kinetic energy (E) of emitted Photoelectrons and the frequency of incident radiation (\(ν\)) is show correctly in figure

The ratio of intensities at two points on the screen in Young's double slit experiment when waves from the two slits have a path difference of zero and \(λ/4\) is (\(λ\) is the wavelength of light used) (\(cos0^{\circ} = 1\), \(cosπ/2 = 0\))

A simple microscope is used to see the object first in blue light and then in red light. Due to the change from blue to red light, what is the effect on its magnifying power?

With gradual increase in frequency of an a.c. supply, the impedance of an LCR series circuit

When a capacitor is connected in series LR circuit, the alternating current flowing in the circuit