List of top Physics Questions

A direct current of 5A is superposed on an alternating current I = 10sin ω t flowing through a wire. The effective value of the resulting current will be
Two particles X and Y having equal charges, after being accelerated through the same potential difference, enter a region of uniform magnetic field and describe circular paths of radii R₁ and R₂ respectively. The ratio of masses of X and Y is
A planoconvex lens fits exactly into a planoconcave lens. Their planar surfaces are parallel to each other. If the lenses are made of different materials of refractive indices mu₁ and mu₂ and R is the radius of curvature of the curved surface, then focal length of the combination is
The position of a projectile launched from the origin at t = 0 is given by r = (40hati + 50hatj)m at t = 2s. If the projectile was launched at an angle θ from the horizontal (take g = 10m s⁻2), then θ is
Water is flowing on a horizontal fixed surface such that its flow velocity varies with y (vertical direction) as v = k((2y²)/(a²) - (y³)/(a³)). If coefficient of viscosity for water is η, what will be the shear stress between layers of water at y = a?
In an ore containing uranium, the ratio of U²38 to Pb²06 is 3. Calculate the age of the ore, assuming that all the lead present in the ore is the final stable product of U²38. Take the half-life of U²38 to be 4.5 × 10⁹ yr.
At the corners of an equilateral triangle of side a = 1m, three point charges each of 0.1C are placed. If the system is supplied energy at the rate of 1kW, calculate the time required to move one of the mid-point of the line joining the other two.
The resistance of a wire is R. It is bent at the middle by 180^∘ and both ends are twisted together to make a short of the new wire. The resistance of the new wire is
The resistance of a wire is R. It is bent at the middle by 180^∘ and both the ends are twisted together to make a shorter wire. The resistance of the new wire is
A body is thrown vertically upwards from A, the top of a tower, and reaches the ground in time t₁. If it is thrown vertically downwards from A with the same speed, it reaches the ground in time t₂. If it is allowed to fall freely from A, then the time taken to reach the ground is
An elastic string of unstretched length L and force constant k is stretched by a small length x. It is further stretched by another small length y. The work done in the second stretching is
A conducting square loop is placed in a magnetic field B with its plane perpendicular to the field. The sides of the loop start shrinking at a constant rate α. The induced emf in the loop at the instant when its side is a is
A charged particle moving in a uniform magnetic field loses 4% of its kinetic energy. The radius of curvature of its path changes by
Calculate the wavelength of light used in an interference experiment from the following data: Fringe width = 0.03cm. Distance between the slits and eyepiece through which the interference pattern is observed is 1m. Distance between the images of the virtual source when a convex lens of focal length 16cm is used at a distance of 80cm from the eyepiece is 0.8cm.
A solid sphere of radius R has a charge Q distributed in its volume with a charge density ρ = krᵃ, where k and a are constants and r is the distance from centre. If the electric field at r = (R)/(2) is (1)/(8) times that at r = R, the value of a is
The displacement of a particle is given at time t, by: x = Asin(-2ω t) + Bsin² ω t Then,
Two tuning forks with natural frequencies 340 Hz each move relative to a stationary observer. One fork moves away from the observer, while the other moves towards the observer at the same speed. The observer hears beats of frequency 3 Hz. Find the speed of the tuning forks.
An artificial satellite is moving in a circular orbit around the earth with a speed equal to half the magnitude of the escape velocity from the earth. The height h of the satellite above the earth’s surface is (Take radius of earth as Rₑ):
Potential energy of a body of mass $1\, kg$ free to move along X-axis is given by $U(x) = \left( \frac{x^2}{2} - x \right) J .$ If the total mechanical energy of the body is $2\, J$. then the maximum speed of the body is (Assume only conservative force acts on the body)
If only $\frac{1}{51}^{th}$ ot the main current is to be passed through a galvanometer then the shunt required is $R_1$ and if only $\frac{1}{11}^{th}$ of the main voltage is to be developed across the galvanometer, then the resistance required is $R_2$. Then $\frac{R_2}{R_1} =$
For a particle executing simple harmonic motion, the displacement-time $(x - t)$ graph is as shown in the figure. The acceleration of the particle at $t = \frac{4}{3} s$ is
An $\alpha$-particle moves in a circular path of radius $1\, cm$ in a uniform magnetic field of $0.125\, T$. The de Broglie wavelength associated with the $\alpha$-particle is
The velocity of an object moving in a straight line path is given as a function of time by $v = 6t - 3t^2$. where $v$ is in $ms^{-1} , t $ is in $s$. The average velocity of the object between $t = 0$ and $t = 2s$ is
In a nuclear reactor the activity of a radioactive substance is $2000 / s$. If the mean life of the products is $50$ minutes, then in the steady power generation, the number of radio nuclides is
The speed of a particle changes from $\sqrt{5} \,ms^{- 1}$ to $2 \sqrt{5} \; ms^{-1}$ in a time If the magnitude of change in its velocity is $5 \; ms^{-1}$, the angle between the initial and final velocities of the particle is