List of top Physics Questions

The percentage decrease in the weight of a rocket, when taken to a height of 32 km above the surface of earth will, be:
(Radius of earth = 6400 km)
Two planets A and B of equal mass are having their period of revolutions TA andTB such that TA= 2TB. These planets are revolving in the circular orbits of radii rA and rB respectively. Which out of the following would be the correct relationship of their orbits?
The time period of a satellite revolving around earth in a given orbit is 7 hours. If the radius of orbit is increased to three times its previous value, then approximate new time period of the satellite will be
The area of cross section of the rope used to lift a load by a crane is \(2.5 × 10^{–4}\) \(m^2\). The maximum lifting capacity of the crane is \(10\) metric tons. To increase the lifting capacity of the crane to \(25\) metric tons, The required area of cross section of the rope should be
The variation of acceleration due to gravity (g) with distance (r) from the center of the earth is correctly represented by
(Given R = radius of earth)
A ball of mass 0.5 kg is dropped from the height of 10 m. The height, at which the magnitude of velocity becomes equal to the magnitude of acceleration due to gravity, is ___ m.
[Use g = 10 m/s2]
The elongation of a wire on the surface of the earth is 10–4m. The same wire of same dimensions is elongated by 6 × 10–5m on another planet. The acceleration due to gravity on the planet will be ___ ms–2. (Take acceleration due to gravity on the surface of earth = 10 ms–2)
A body of mass m is projected with velocity λve in vertically upward direction from the surface of the earth into space. It is given that ve is escape velocity and λ< 1. If air resistance is considered to be negligible, then the maximum height from the centre of earth, to which the body can go, will be:
(R : radius of earth)
Two objects of equal masses placed at certain distance from each other attracts each other with a force of F. If one-third mass of one object is transferred to the other object, then the new force will be
The aperture of the objective is 24.4 cm. The resolving power of this telescope, if a light of wavelength 2440 Å is used to see the object will be:

A thin prism of angle 6° and refractive index for yellow light (nY)1.5 is combined with another prism of angle 5° and nY = 1.55. The combination produces no dispersion. The net average deviation (δ) produced by the combination is (1/x)°. The value of x is __________.

Fig. Prism
The difference of speed of light in the two media A and B(υA – υB) is 2.6 × 107 m/s. If the refractive index of medium B is 1.47, then the ratio of refractive index of medium B to medium A is: (Given: speed of light in vacuum C = 3 × 108 ms–1)
The power of a lens (biconvex) is \(1.25 m^{–1}\) in particular medium. Refractive index of the lens is \(1.5\), and the radii of curvature are \(20 cm\) and \(40 cm\), respectively. The refractive index of surrounding medium
A signal of 100 THz frequency can be transmitted with maximum efficiency by :
A parallel beam of light of wavelength 900 nm and intensity 100 Wm–2 is incident on a surface perpendicular to the beam. The number of photons crossing 1 cm–2 area perpendicular to the beam in one second is
A small bulb is placed at the bottom of a tank containing water to a depth of √7 m. The refractive index of water is 4/3. The area of the surface of water through which light from the bulb can emerge out is xπ m2. The value of x is ________.
The refracting angle of prism is A and refractive index of material of prism is $\cot \frac{A}{2}$ The angle of minimum deviation is
A light wave travelling linearly in a medium of dielectric constant 4, incidents on the horizontal interface separating medium with air. The angle of incidence for which the total intensity of incident wave will be reflected back into the same medium will be:
(Given : relative permeability of medium μr = 1)
As shown in the figure, after passing through the medium 1. The speed of light v2 in medium 2 will be: (Given \(c = 3 \times 10^8 ms^{-1}\))
speed of light v2 in medium 2
In normal adjustment, for a refracting telescope, the distance between objective and eye piece is $30\,cm$ The focal length of the objective, when the angular magnification of the telescope is 2, will be:
A microscope was initially placed in air (refractive index 1). It is then immersed in oil (refractive index 2). For a light whose wavelength in air is λ, calculate the change of microscope’s resolving power due to oil and choose the correct option.

A wire X of length 50 cm carrying a current of 2 A is placed parallel to a long wire Y of length 5 m. The wire Y carries a current of 3 A. The distance between two wires is 5 cm and currents flow in the same direction. The force acting on the wire Y is

A wire X of length 50 cm carrying a current of 2 A is placed parallel to a long wire Y of length 5 m

A 8 V Zener diode along with a series resistance R is connected across a 20 V supply (as shown in the figure). If the maximum Zener current is 25 mA, then the minimum value of R will be ____ Ω.

A 8 V Zener diode along with a series resistance R is connected across a

In a Young's double slit experiment, the intensity of light at a point on the screen where the path difference between the interfering waves is $\lambda$ (where $\lambda$ is the wavelength of light used) is $1$. The intensity at a point where the path difference is $\frac{\lambda}{4}$ will be (assume two waves have the same amplitude)
A straight wire is placed in a magnetic field that varies with distance $x$ from origin as $B = B_0 (2 - \frac{x}{n}) \hat{k}$. The ends of the wire are at $(a, 0)$ and $(2n, 0)$ and it carries a current $I$. If the force on the wire is $F = 1 B_0 \left(\frac{k a}{2}\right) \hat{j}$, then the value of $k$ is