List of top Physics Questions

For a transistor $\alpha$ and $\beta$ are given as $\alpha = \frac{I_C}{I_E}$ and $\beta = \frac{I_C}{I_B}$. Then the correct relation between $\alpha$ and $\beta$ will be :

An antenna is mounted on a 400 m tall building. What will be the wavelength of signal that can be radiated effectively by the transmission tower upto a range of 44 km ?

If force (F), length (L) and time (T) are taken as the fundamental quantities. Then what will be the dimension of density:

A coaxial cable consists of an inner wire of radius 'a' surrounded by an outer shell of inner and outer radii 'b' and 'c' respectively. The inner wire carries an electric current $i_0$, which is distributed uniformly across cross-sectional area. The outer shell carries an equal current in opposite direction and distributed uniformly. What will be the ratio of the magnetic field at a distance x from the axis when (i) x $<$ a and (ii) a $<$ x $<$ b?

For full scale deflection of total 50 divisions, 50 mV voltage is required in galvanometer. The resistance of galvanometer if its current sensitivity is 2 div/mA will be :

A mass of 50 kg is placed at the centre of a uniform spherical shell of mass 100 kg and radius 50 m. If the gravitational potential at a point, 25 m from the centre is V. The value of V is:

If the rms speed of oxygen molecules at 0$^{\circ}$C is 160 m/s, find the rms speed of hydrogen molecules at 0$^{\circ}$C.

The height of victoria falls is 63 m. What is the difference in temperature of water at the top and at the bottom of fall?
[Given 1 cal = 4.2 J and specific heat of water = 1 cal g$^{-1}$ $^{\circ}$C$^{-1}$]

A player kicks a football with an initial speed of 25 ms$^{-1}$ at an angle of 45$^{\circ}$ from the ground. What are the maximum height and the time taken by the football to reach at the highest point during motion? (Take g = 10 ms$^{-2}$)

Two discs have moments of inertia I$_1$ and I$_2$ about their respective axes perpendicular to the plane and passing through the centre. They are rotating with angular speeds, $\omega_1$ and $\omega_2$ respectively and are brought into contact face to face with their axes of rotation coaxial. The loss in kinetic energy of the system in the process is given by:

Water drops are falling from a nozzle of a shower onto the floor, from a height of 9.8 m. The drops fall at a regular interval of time. When the first drop strikes the floor, at that instant, the third drop begins to fall. Locate the position of second drop from the floor when the first drop strikes the floor.

A wooden block of mass 10 kg is moving with an acceleration of 3ms on a rough floor. If the coefficient of friction is 0.3, then the applied force on it is (g=10ms)

The kinetic energy of a particle of mass m executing linear simple harmonic motion with angular velocity $ω$ and amplitude $a$ is $\frac 1{4} ma^2ω^2$ at a distance of _______from the mean position.

The alternating current is given by $i = \{\sqrt{42} \sin(\frac{2\pi}{T}t) + 10\} A$. The r.m.s. value of this current is _________ A.

A rod CD of thermal resistance 10.0 KW$^{-1}$ is joined at the middle of an identical rod AB as shown in figure. The ends A, B and D are maintained at 200$^{\circ}$C, 100$^{\circ}$C and 125$^{\circ}$C respectively. The heat current in CD is P watt. The value of P is _________.

A body of mass (2M) splits into four masses m, M-m, m, M-m, which are rearranged to form a square as shown in the figure. The ratio of $\frac{M}{m}$ for which, the gravitational potential energy of the system becomes maximum is x : 1. The value of x is ________.

A circuit is arranged as shown in figure. The output voltage $V_o$ is equal to ________ V.

When a copper wire is connected to a battery the electric field in the wire is

Pick the false statement on the magnetic field lines.

When freely suspended, the compass needle come to rest along the geographic

A bar magnet is passing through a conducting loop of radius R with velocity v. The radius of the bar magnet is such that it just passes through the loop. The induced e.m.f. in the loop can be represented by the approximate curve :

Calculate the amount of charge on capacitor of 4 $\mu$F. The internal resistance of battery is 1 $\Omega$:

The variation of displacement with time of a particle executing free simple harmonic motion is shown in the figure.
The potential energy U(x) versus time (t) plot of the particle is correctly shown in figure :

The resultant of these forces $\vec{OP}, \vec{OQ}, \vec{OR}, \vec{OS}$ and $\vec{OT}$ is approximately ________ N.
[Take $\sqrt{3} = 1.7, \sqrt{2} = 1.4$. Given $\hat{i}$ and $\hat{j}$ unit vectors along x, y axis]

A transmitting antenna has a height of 320 m and that of receiving antenna is 2000 m. The maximum distance between them for satisfactory communication in line of sight mode is 'd'. The value of 'd' is _________ km. (Radius of Earth = 6400 km)