List of top Physics Questions

A common emitter amplifier gives an output of $ 3 \,V $ for an input of $ 0.01 \,V $ . If $ \beta $ of the transistor is $100$ and the input resistance is $ 1\text{ }k\Omega , $ then the collector resistance is
The quantities RC and $ \left( \frac{L}{R} \right) $ ( where $R, L$ and $C$ stand for resistance, inductance and capacitance respectively ) have the dimensions of
A body of mass $60 \,kg$ suspended by means of three strings $P, Q$ and $R$ as shown in the figure is in equilibrium. The tension in the string $P$ is
The direction of propagation of electromagnetic wave is along
The area under velocity-time graph for a particle in a given interval of time represents
Given below are two statements, one is labelled as Assertion A and the other is labelled as Reason R
Assertion(A): Electric field is discontinuous across the surface of a spherical charged shell
Reason (R): Electric potential is continuous across the surface of a spherical charged shell
In the light of the above statements, choose the correct answer from the options given below
Three point charges q, - 2q and - 2q are placed at the vertices of an equilateral triangle of side a. The work done by some external force to in crease their separation to 2a will be
As per this diagram a point charge +q is placed at the origin O. Work done in taking another point charge -Q from the point A [co-ordinates (0,a)] to another point B [coordinates (a,0)] along the straight path AB is:
 
a point charge +q is placed at the origin O
A solid cylinder rolls down an inclined plane of height 3 m and reaches the bottom of plane with angular velocity, of 2 $ \sqrt {2} rads ^{-1} $ . The radius of cylinder must be (Take g = 10 $ ms ^{-2}$ )
A wire of natural length $ l, $ Youngs modulus $ Y $ and area of cross-section $ A $ is extended by $ x $ . Then the energy stored in the wire is given by
After terminal velocity is reached, the acceleration of a body falling through a fluid is
A transverse wave is described by the equation $ y={{y}_{0}}\sin 2\pi \left( ft-\frac{x}{\lambda } \right). $ The maximum particle velocity is equal to four times the wave velocity, if
A ray of light passes through an equilateral prism such that an angle of incidence is equal to the angle of emergence and the latter is equal to $ \frac{3}{4} $ th the angle of prism. The angle of deviation is:
If the unit of force and length are doubled, the unit of energy will be
A stone falls freely from rest from a height $h$ and it travels a distance $\frac{9h}{25}$ in the last second. The value of $h$ is
A particle of mass m is moving along the x-axis under the potential $V (x) = \frac{kx^2}{2} + \frac{\lambda}{x}$, where $k $ and $\lambda$ are positive constants of appropriate dimensions. The particle is slightly displaced from its equilibrium position. The particle oscillates with the angular frequency $\omega$ given by
A particle of mass $m$ and charge $q$ with an initial velocity $v$ is subjected to a uniform magnetic field $B$ along the vertical direction. The particle will
Identify the mismatched pair from the following
An electric dipole consists of two opposite charges each 0.05 $\mu$C separated by 30 mm. The dipole is placed in an uniform external electric field of $ 10^6 \, NC^{ - 1}$. The maximum torque exerted by the field on the dipole is
The length of a rubber cord is $ {{l}_{1}} $ metre when the tension is $ 4\, N $ and $ {{l}_{2}} $ metre when the tension is $ 6\, N $ . The length when the tension is $9\,N$, is
A voltage $V_{PQ} = V_0 \, \cos \, \omega t$ (where $V_0$ is a real amplitude) is applied between the points P and Q in the network shown in the figure. The values of capacitance and inductance are $C = \frac{1}{\omega R \sqrt{3}}$ and $L = \frac{R \sqrt{3}}{\omega}$ Then, the total impedance between P and Q is
For signal transmission, modulation is necessary
Two planets have radii $r_1$ and $r_2$ and densities $d_1$ and $d_2$ respectively. Then the ratio of accelerations due to gravity on them is
A pendulum of length 1 m is released from $\theta$ = 60$^{\circ}$. The rate of change of speed of the bob at $\theta$= 30$^{\circ}$ is $(g=10 \, ms^{-1})$
A tank is filled with water of density 1 gcm3 and oil of density 0.9 gcm3. The height of water layer is 100 cm and that of oil layer is 400 cm. If g=980 cms2, then the velocity of efflux from an opening in the bottom of the tank will be-