List of practice Questions

A stretched string of length $l$, fixed at both ends, can sustain Stationary waves of wavelength of wavelength $\lambda,$ correctly given by
A straight line is such that the sum of the reciprocals of its intercepts on the axes is K.Then it passes through the fixed point with co-ordinates
A straight line through the point A (3, 4) is such that its intercept between the axes is bisected at A. Its equation 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 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 stone is thrown vertically upwards with kinetic energy K. The kinetic energy at the highest point is
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 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 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 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 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 body of mass m explodes into 3 parts of masses m in the ratio 1 : 3 : 3, its two fractions having equal masses moving at right angles to each other with a velocity of 15 $ms^{-1}$. What is the velocity of the third body
A stationary hydrogen atom emits photon corresponding to the first line of Lyman series. If R is the Rydberg's constant and M is the mass of the atom, then the velocity acquired by the atom is (neglect energy absorbed by the photon)
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
A square wire of side 3.0 cm is placed 25 cm away from a concave mirror of focal length 10 cm. What is the area enclosed by the image of the wire? (The square wire is placed such that the centre of the wire on the axis of the mirror with its two sides normals to the axis):
A standard hydrogen electrode has a zero potential because
A square of side $L$ meters lies in the $x-y$ plane in a region, where the magnetic field is given by $\vec{B}= B_0 (2\hat{i} + 3\hat{j} +4\hat{k})T$ where $B_0$ is constant. The magnitude of flux passing through the square is
A square of side $x \,m$ lies in the $x$-$y$ plane in a region, where the magnetic field is given by $\vec{B}=B_{0}\left(3\hat{i}+4\hat{j}+5\hat{k}\right)T$, where $B_{0}$ is constant. The magnitude of flux passing through the square is
A square piece of tin of side $24\, cm$ is to be made into a box without top by cutting a square from each corner and folding up the flaps to form a box. What should be the side of the square to be cut off so that the volume of the box is maximum?