List of top Physics Questions

A circular coil of radius 25 cm, carries a current of 50 amperes. I f it has 35 turns, the flux density at the centre of the coil is (in $Wb/m^2$)
A circular coil of radius $6\, cm$ and $20$ turns rotates about its vertical diameter with an angular speed of $40\, rad \, s^{-1}$ in a uniform horizontal magnetic field of magnitude $2 \times 10^{-2}\, T$. If the coil form a closed loop of resistance $8 \,\omega$, then the average power loss due to joule heating is
A circular coil of radius $8\, cm$, $400$ turns and resistance $2 \,Omega$ is placed with its plane perpendicular to the horizontal component of the earths magnetic field. It is rotated about its vertical diameter through $180^{\circ}$ in $0.30\, s$. Horizontal component of earth magnetic field at the place is $3\times 10^{-5}\, T$ The magnitude of current induced in the coil is approximately
A circular coil of 100 turns and effective diameter 20cm carries a current of 0.5 A. It is to be turned in a magnetic field of B = 2.0 T from a position in which the normal to the plane of the coil makes an angle $\theta$ equals to zero to one in which $\theta$ equals to 180$^\circ$. The work required in this process is
A circular coil of 16 turns and radius 0.1 m carries a current of 0.75 A . Its plane is normal to the external magnetic field of strength 0.05T . When the coil is turned slightly, it oscillates with a frequency of 2 Hz. Calculate the moment of inertia of the coil about the axis of rotation
A circular coil of diameter 2 cm and 100 turns is placed at the centre of a long solenoid of radius 5 cm and 10 turns/cm. The mutual inductance of the two coils will be nearest to:
A child is standing at one end of a long trolley moving with a speed $v$ on a smooth horizontal floor. If the child starts running towards the other end of the trolley with a speed $u$, the centre of mass of the system (trolley + child) will move with a speed
A child is standing with his two arms outstretched at the centre of a turntable that is rotating about its central axis with an angular speed $\omega_0$ . Now, the child folds his hands back so that moment of inertia becomes $3$ times the initial value. The new angular speed is
A charged particle with charge $q$ enters a region of constant, uniform and mutually orthogonal fields $\vec{E}$ and $\vec{B}$ with a velocity $\vec{V}$ perpendicular to both $\vec{E}$ and $\vec{B}$, and comes out without any change in its magnitude or direction Then
A charged particle of charge Q arid mass m moves with velocity v in a circular path due to transverse magnetic field, B, then its frequency is
A charged oil drop is suspended in uniform field of $3 \times 10^4\, V/m$ so that it neither falls nor rises. The charge on the drop will be (Take the mass of the charge $= 9.9 \times 10^{-15}\, kg$ and $g = 10\, m/s^2)$
A certain radioactive substance has a half-life of 5 years. Thus for a nucleus in a sample of the element, the probability of decay in ten years is
A chain reaction in fission of Uranium is possible because
A Centigrade and Fahrenheit thermometers are dipped in boiling water. The water temperature is lowered until the Fahrenheit thermometer registers a temperature of 140?. The fall of temperature as registered by the Centigrade thermometer is:
A cavity of radius $\frac{R}{2}$ is made inside a solid sphere of radius R . The center of the cavity is located at a distance $\frac{r}{2}$ from the center of sphere. The gravitational force on a particle of mass m at a distance $\frac{R}{2}$ from the center of the sphere on the line joining both the centers of sphere and cavity is ( opposite to the center of cavity ) [ here $g=\frac{GM}{R^2}$ where M the mass of the sphere ].
A cart is moving horizontally along a straight line with constant speed 30 m/s. A projectile is to be fired from the moving cart in such a way that it will return to the cart after the cart has moved 80 m. At what speed (Relative to the cart) must the projectiie be fired? (Take g = $ 10 \, ms^{ - 2} $ )
A car starts from rest and travels with uniform acceleration $\alpha$ for some time and then With uniform retardation $\beta$ and comes to rest If the total time of travel of the car is 't' the maximum velocity attained by it is given by
A car travels first half distance between the places with a speed of $30\, km \,h^{-1}$ and remaining half with a speed of $50\, km \, h^{-1}$. The average speed of car is
A car weighs $1800 \,kg$. The distance between its front and back axles is $1.8 \,m$. Its centre of gravity is $1 \,m$ behind the front axle. The force exerted by the level ground on each front wheel and each back wheel is (Take $g = 10\, m s^{-2})$
A car, starting from rest, accelerates at the rate f through a distance S, then continues at: constant speed for time t and then decelerate at the rate $\frac{f}{2}$ to come to rest. If the total distance travelled is 15S, then
A car is moving in a circular path of radius 500 m with a speed of 30 $ms^{-1}$. If the speed is increasing at the rate of 2 $ms^{-2}$ the resultant acceleration will be
A car moving along a straight highway with speed of $126Kmh^{-1} $ is brought to a stop with in a distance of 200m. what is the retardation of the car
A car is moving on a circular level road of curvature 300 m. If the coefficient of friction is $0.3$ and acceleration due to gravity is $10\,m\, s^{-2}$, the maximum speed of the car can be
A car covers the first one-third of a distance x at a speed of $10\, km\, h^{-1}$, the second one-third at a speed of $20\, km\, h^{-1}$ and the last one-third at a speed of $60\, km \,h^{-1}$. Find the average speed of the car over the entire distance x.
A car drives along smooth straight level road by an engine giving constant power. The velocity is directly proportional to