List of top Physics Questions

Along a streamline
Air inside a closed container is saturated with water vapour. The air pressure is p and the saturated vapour pressure of water is $\overline{p}$. If the mixture is compressed to one-half of its volume by maintaining temperature constant, the pressure becomes
Air has refractive index 1.0003. The thickness of air column which will have one more wavelength of yellow light (600 nm) than in the same thickness of vacuum is:
According to the Hooke's law, the force required to change the length of a wire by 'l' is proportional to :
According to second postulate of Bohr model, the angular momentum $(L_n)$ of $n^{th}$ possible orbit of hydrogen atom is given by
According to Newtons formula, the speed of sound in air at $STP$ is (Take the mass of $1$ mole of air is $29 \times 10^{-3}\, kg$)
According to Classical theory, the Rutherford model of atom is
According to Laplace correction, the propagation of sound in gas takes place under
According to Hooke?? law of elasticity, if stress is increased, the ratio of stress to strain
According to Bohr hypothesis, discrete quantity is
According to Bohr?? theory, the wave number of last line of Balmer series is $(R = 1.1 \times 10^7 \,m^{-1})$
About $6\%$ of the power of a $100\, W$ light bulb is converted to visible radiation. The average intensity of visible radiation at a distance of $8\, m$ is (Assume that the radiation is emitted isotropically and neglect reflection.
A120 V, 60Hz a.c. power is connected $800\Omega$ non-inductive resistance and unknown capcitance in series. The voltage drop across the resistance is found to be 102V, then voltage drop across eapacitor is
A wire of resistance R is elongated n-fold to make a new uniform wire. The resistance of new wire
A wire of length $L$, radius $r$ when stretched with a force $F$ changes in length by $l$. What will be the change in the length of a wire of same material having length $2L$, radius $2r$ and stretched by a force $2F$ ?
A wire is stretched between two rigid supports vibrates in its fundamental mode with a frequency of $50 \,Hz$. The mass of the wire is $30 \,g$ and its linear density is $4 \times 10^{-2}\, kg \,m s^{-1}$. The speed of the transverse wave at the string is
A wire is stretched to double its length. The strain is :
A wire of length $L$ has a linear mass density $\mu$ area of cross-section $A$ and Young?? modulus Y. It is suspended vertically from a rigid support. The extension produced in the wire due to its own weight is
A wire has a mass $(0.3 \pm 0.003)\, g$, radius $(0.5 \pm 0.005)\,cm$ and length $(6 \pm 0.06) \,cm$. The maximum percentage error in the measurement of its density is
A wheel with $20$ metallic spokes each of length $0.8 \,m $ long is rotated with a speed of $120$ revolution per minute in a plane normal to the horizontal component of earth magnetic field $H$ at a place. If $H = 0.4 \times 10^{-4}\, T$ at the place, then induced emf between the axle and the rim of the wheel is
A wheel completes $2000$ revolutions to cover the $9.5\,km$ distance, then the diameter of the wheel is
A weight $w$ is suspended from, the mid-point of a rope, whose ends are at the same level. In order to make the rope perfectly horizontal, the force applied to each of its ends must be
A water tank standing on the floor has two small holes vertically one above the other punched on one side. The holes are $h_1$ cm and $h_2$ cm above the floor. How high does water stand in the tank when the jets from the holes hit the floor at the same point ?
A vibration magnetometer consists of two identical bar magnets placed one over the other such that they are mutually perpendicular and bisect each other. The time period of oscillations of combination in a horizontal magnetic field is 4s. If one of the magnets is removed, then the period of oscillations of the other in the same field is
A watch glass containing some powdered substance is placed between the pole pieces of a magnet. Deep concavity is observed at the centre. The substance in the watch glass is (assume poles are far)