List of practice Questions

A Carnot?s engine operates with source at $127?C$ and sink at $ 27?C$. If the source supplies 40 kJ of heat energy, the work done by the engine is
A wire suspended vertically from one of its ends is stretched by attaching a weight of 200 N to the lower end. The weight stretches the wire by 1 mm. Then the elastic energy stored in the wire is
Two capillary tubes of radii 0.2 cm and 0.4 cm are dipped in the same liquid. The ratio of heights through which liquid will rise in the tubes is
A block of wood floats in water with $\left( \frac{4}{5} \right)^{th}$of its volume submerged. If the same block just floats in a liquid, the density of the liquid (in Kg m$^{-3}$) is
A boy walks to his school at a distance of 6 km with constant speed of ${2.5\, km \, h^{-1}}$ and walks back with a constant speed of ${4\, km \, h^{-1}}$. His average speed for round trip expressed in ${ km \, h^{-1}}$, is
From the top of a tower of height 40 m, a ball is projected upwards with a speed of ${20 \,m \, s^{-1}}$ at an angle of elevation of 30?. Then the ratio of the total time taken by the ball to hit the ground to its time to same height is Take ${g = 10 \, m \, s^{-2}}$
Two bars $A$ and $B$ of circular cross-section and of same volume and made of the same material are subjected to tension. If the diameter of $A$ is half that of $B$ and if the force applied to both the rods is the same and it is in the elastic limit, the ratio of extension of $A$ to that of $B$ will be
A 280 day old radioactive substance shows an activity of 6000 dps, 140 days later its activity becomes 3000 dps. What was its initial activity?
Which of the following hormones contains iodine?
Which of the following is not true for $S_N1$ reaction ?
Which of the following is the correct pathway of absorbed water in the roots of plants ?
Which of the following statements is not true for Nostoc ?
X-rays, gamma rays and microwaves travelling in vacuum have
Two thin plano-convex lenses each of focal length $f$ are placed as shown in the figure. The ratio of their effective focal lengths in the three cases is
The value of $^{10}C_1+^{10}C_2+^{10}C_3+....+^{10}C_9 $ is
The $pH$ of the solution obtained by mixing $100\, ml$ of a solution of $pH = 3$ with $400\, ml$ of a solution of $pH = 4$ is
The correct order of electronegativities of $N, O, F$ and $P$ is
Sucrose is NOT a reducing sugar since
Power alcohol is a mixture of
In the loop shown, the magnetic induction at the point $O$ is
If father shows normal genotype and mother shows a carrier trait for haemophilia:
A planet moving around sun sweeps area $A_1$ in $2$ days, $A_2$ in $3$ days and $A_3$ in $6$ days. Then the relation between $A_1, A_2 $ and $A_3$ is
When a mass is rotating in a plane about a fixed point, its angular momentum is directed along
The common bottle cork is a product of
If $v_e$ is escape velocity and $v _o$ is orbital velocity of a satellite for orbit close to the earth's suface, then these are related by