List of top Physics Questions

A thin glass (refractive index $1.5$) lens has optical power of $-8\, D$ in air. Its optical power in a liquid medium with refractive index $1.6$ will be
A thin circular ring of area A is perpendicular to uniform magnetic field of induction B. A small cut is made in the ring and a galvanometer is connected across the ends such that the total resistance of circuit is R. When.the ring is suddenly squeezed to zero area, the charge flowing through the galvanometer is
A tensile force of $2\times10^5$ dynes doubles the length of an elastic cord whose area of cross section is 2scm Young's modulus of the material of the cord is
A structural steel rod has a radius of 10 mm and a length of 1 m. A 100 kN force stretches it along its length. The strain on the rod is $(Y_{steel} = 200 ? 10^9 \,N \,m^{-2})$
A string of length l hangs freely from a rigid support. The time required by a transverse pulse to travel from bottom to half length of the string is
A string of length $l$ fixed at one end carries a mass m at the other end. The string makes $ \frac{ 2}{ \pi } $ rev/s around the horizontal axis through the fixed end as shown in the figure, the tension in the string is
A strong magnetic field is applied on a stationary electron. Then the electron
A stretched string of length $l$, fixed at both ends, can sustain Stationary waves of wavelength of wavelength $\lambda,$ correctly given by
A straight wire (conductor) of length 10 cm is kept in a uniform magnetic field of induction 0.02 T. The angle between the conductor and the-field direction is 30. A current of 5A is passed through the conductor. The force on the conductor is (in N)
A stream of water flowing horizontally with a speed of $15 m \,s^{-1}$ gushes out of a tube of cross-sectional area $10^{-2}$ $m^{2}$, and hits a vertical wall normally. Assuming that it does not rebound from the wall, the force exerted on the wall by the impact of water is
A stone of mass $m$ is tied to a string and is moved in a vertical circle of radius $r$ making n rev/min. The total tension in the string when the stone is at the lowest point is
A stone thrown vertically upwards with a speed of 5 m/sec attains a height $H_1$. Another stone thrown upwards from the same point with a speed of 10 m/sec attains a height $H_2$. The correct relation between $H_1$ and $H_2$ is
A stone of mass $5 \,kg$ is tied to a string of length $10 \,m$ and is whirled round in a horizontal circle. What is the maximum speed with which the stone can be whirled around if the string can withstand a maximum tension of $200 \,N$?
A stone is thrown vertically upwards with kinetic energy K. The kinetic energy at the highest point is
A stone is dropped from the window of a train moving along horizontal straight track with contant velocity. The path of the stone is
A stone is projected vertically up from the ground With velocity $40 ms^{-1}$ The interval of time between the two instants at which the stone is at a height of 60 m above the ground is $(g = 10 ms^{-2})$
A step-up transformer works on 220V and gives 2 A to an external resistor. The turn ratio between the primary and secondary coils is 2:25. Assuming 100% efficiency, find the secondary voltage. Primary current and power delivered.
A step up transformer operates on a $230V$ line and a load current of $2A$. The ratio of the primary and secondary windings is $1\,:\, 25$. The current in the primary is
A step up transformer raises the voltage from 220V to 11000V. If the number of turns of the secondary be 1000, the number of turns of the primary is
A steel wire is 1 m long and 1mm$^2$ in area of cross-section. If it takes 200 N to stretch this wire by I mm how much force will be required to stretch the wire of the same area and of same material having length of 10m to 1002 cm
A steel wire of length 4.7m and cross sectional area $3 \times 10^{-6}m^2$ stretches by the amount as a copper wire of length 3.5m and cross-sectional area of $4 \times 10^{-6}m^2$ under a given load. The ratio of young's modulus of steel to that of copper is
A steel tape is calibrated at $20^{\circ} C$. when the temperature of the day is $-10^{\circ} C$ , the percentage error in the measurement with the tape is $\alpha=12 \times 10^{-6}\,/^{\circ} C)$
A steel rod of length $100 \,cm$ is clamped at the middle. The frequency of the fundamental mode for the longitudinal vibrations of the rod is (Speed of sound in steel $= 5\, km\, s^{-1})$
A stationary wheel starts rotating about its own axis at uniform angular acceleration $8rad/s^2.$ The time taken by it to complete rotations is
A stationary police car sounds a siren with a frequency of 990 Hz. If the speed of sound is 330 m/s, an observer, driving towards the car with a speed of 33 m/s, will hear a frequency of