List of top Physics Questions

Two soap bubbles of volumes \( 27V \) and \( 64V \) coalesce under isothermal conditions. The volume of the bigger bubble formed is:
In moving a body of mass \( m \) down a smooth incline of inclination \( \theta \) with velocity \( v \), the power required is (g = acceleration due to gravity):
The ratio of the centripetal accelerations of the electron in two successive orbits of hydrogen is 81:16. Due to a transition between these two states, the angular momentum of the electron changes by:
If the number of electron-hole pairs per cm\(^3\) of an intrinsic Si wafer at temperature 300 K is \(1.1 \times 10^{10}\) and the mobilities of electrons and holes at 300 K are 1500 and 500 cm\(^2\) per volt, second, respectively, then the conductivity of the Si wafer at this temperature (in \(\mu\)mho cm\(^{-1}\)) is nearly:
The minimum energy required to launch a satellite of mass m from the surface of earth of mass M and radius R in a circular orbit at an altitude of 2R from the surface of the earth is :
In a radioactive sample \( 2 \times 10^8 \) nuclei reduce to \( 10^8 \) nuclei in 15 minutes, then the half-life of the sample in minutes is:
If R is the resistance of a conductor of length l, then
The power of a lens of focal length 20 cm is
If the ratio of the absolute temperature of the sink and source of a Carnot engine is changed from 2:3 to 3:4, the efficiency of the engine changes by:
An ink mark is made on a piece of paper and a glass slab of thickness $t$ and refractive index $\mu$ is placed on it. If the image of the ink mark appears to be at a distance of $x$ from the top surface of the slab, then the value of $x$ is
The position vector of a particle of mass \(m\) moving with a constant velocity \(\mathbf{u}\) is given by \(\mathbf{r} = x(t)\hat{i} + b\hat{j}\), where \(b\) is a constant. At an instant, \(\mathbf{r}\) makes an angle \(\theta\) with the x-axis as shown in the figure. The variation of the angular momentum of the particle about the origin with \(\theta\) will be:
Ques Fig
A rectangular tank of depth 4 m is full of water of refractive index \(\frac 43\). When viewed from the top, the bottom of the tank is seen at a depth of
If \(v_1\) and \(v_2\) are the speeds of light in the two media of refractive indices \(n_1\) and \(n_2\) respectively, then
If a body is taken above the surface of the Earth, it loses its weight by 20% at a height of \( h = \frac{\sqrt{5}}{2} R \), where \( R \) is the radius of the Earth, then:
In the following OP-AMP circuit, 𝑣𝑖𝑛 and π‘£π‘œπ‘’π‘‘ represent the input and output signals, respectively.
OP-AMP circuit
Choose the correct statement(s):
When two spheres of radii $r$ and $\frac{r}{2}$ are brought in contact, the gravitational force of attraction between them is proportional to
In the measurement of length 6 $\mu$m is equal to $x$ pm. Then the value of $x$ is
A string of length \( L \) is fixed at both ends and vibrates in its fundamental mode. If the speed of waves on the string is \( v \), then the angular wave number of the standing wave is:
The maximum velocity of a fluid in a tube for which the flow remains streamlined is called its:
A wooden block of mass 6 kg is pulled across a rough surface by a 54 N force against a friction force \( F \). The acceleration of the block is \( 6 \, \text{m/s}^2 \). Then the value of friction force \( F \) is:
An object of 4.0 cm in size is placed at 25 cm in front of a concave mirror of focal length 15 cm. At what distance from the mirror should a screen be placed in order to obtain a sharp image?
\( V_V, V_R, V_G \) are the velocities of violet, red, and green light respectively, in a glass prism. Which among the following is a correct relation?
The gravitational force between two masses kept at a certain distance is \( P \) Newton. The same two masses are now kept in water and the distance between them is the same. The gravitational force between these two masses in water is \( Q \) Newton. Then:
100 joules of heat is produced each second in a 4 ohm resistance. Potential difference across the resistor is:
A body weighs 75 gm in air, 51 gm when completely immersed in an unknown liquid and 67 gm when completely immersed in water. Find the density of the unknown liquid: