List of top Physics Questions

The minimum value of effective capacitance that can be obtained by combining $3$ capacitors of capacitances $1\, pF,\, 2\, pF$ and $4\, pF$ is

A jet plane of wing span $20\, m$ is travelling towards west at a speed of $400 \,{ms^{-1}}$. If the earth?s total magnetic field is $4 \times 10^{-4} T$ and the dip angle is $30^\circ$, at that place, the voltage difference developed across the ends of the wing is

The angle between velocity and acceleration of a particle describing uniform circular motion is

Consider a drop of rain water having mass $1\,g$ falling from a height of $1\,km$. It hits the ground with a speed of $50\,m/s$. Take 'g' constant with a value ${10 \, m/s^2}$. The work done by the (i) gravitational force and the (ii) resistive force of air is :-

??ydraulic lift??works on the basis of

Displacement x versus $t^2$ graph is shown for a particle. The acceleration of the particle is :

Two tuning forks A and B produce 4 beats/sec. Forks B and C produce 5 beats/sec. Forks A and C may produce ??. beats/sec

When ${ }^{92} U _{235}$ undergoes fission $0.1 \%$ of its original mass is changed into energy. How much energy is released if $1 \,kg$ of ${ }^{92} U _{235}$ undergoes fission

A $n-p-n$ transistor is connected to common emitter configuration in a given amplifier. A load resistance of $800$ is connected in the collector circuit and the voltage drop across it is $0.8\, V$. If the current amplification factor is $0.96$ and the input resistance of the circuit is $192\,\Omega$, the voltage gain and the power gain of the amplifier will respectively be

A rectangular film of liquid is extended from $(4 \, cm \times 2\, cm)$ to $ (5 \, cm \times 4 \, cm)$. If the work done is $3 \times 10^{-4} \, J$, the value of the surface tension of the liquid is -

An electric dipole is placed at an angle of $30^{\circ}$ with an electric field intensity $2 \times 10^{5} N / C .$ It experiences a torque equal to $4\, Nm$. The charge on the dipole, if the dipole length is $2\, cm$, is

An electron of mass m and a photon have same energy E. The ratio of de-Broglie wavelengths associated with them is :

Consider the junction diode as ideal. The value of current flowing through \(AB\) is :

Electrons of mass $m$ with de-Broglie wavelength $\lambda$ fall on the target in an X-ray tube. The cutoff wavelength $(\lambda_0)$ of the emitted X-ray is

For $CE$ transistor amplifier, the audio signal voltage across the collector resistance of $2 k \Omega$ is $4\, V$. If the current amplification factor of the transistor is $100$ and the base resistance is $1 \, k\Omega$, then the input signal voltage is

When a metallic surface is illuminated with radiation of wavelength $\lambda$ , the stopping potential is V. If the same surface is illuminated with radiation of wavelength $2 \lambda$, the stopping potential is $\frac{V}{4}$ . The threshold wavelength for the metallic surface is :

Three liquids of densities having the same value of surface tension $T$, rise to the same height in three identical capillaries. The angles of contact $\theta_{1}, \theta_{2}$ and $\theta_{3}$ obey-

Two cars $P$ and $Q$ start from a point at the same time in a straight line and their positions are represented by $x _{ P }( t )= at + bt ^{2}$ and $x _{ Q }( t )=f t - t ^{2}$. At what time do the cars have the same velocity ?

An engine of power \( 58.8 \) kW pulls a train of mass \( 2 \times 10^5 \) kg with a velocity of \( 36 \text{ km h}^{-1} \). The coefficient of friction is

Choose the wrong statement in the following

A body is thrown up with a speed \( u \), at an angle of projection \( \theta \). If the speed of the projectile becomes \( \frac{u}{\sqrt{2}} \) on reaching the maximum height, the maximum vertical height attained by the projectile is

An aeroplane is flying with a uniform speed of \( 150 \text{ km h}^{-1} \) along the circumference of a circle. The change in its velocity in half the revolution (in km h\(^{-1}\)) is

A man rides a bicycle with a speed of \( 17.32 \text{ m s}^{-1} \) in east-west direction. If the rain falls vertically with a speed of \( 10 \text{ m s}^{-1} \), the direction in which he must hold his umbrella is

In uniform circular motion, the centripetal acceleration is