List of practice Questions

Find the position of final image from first lens.If the focal length of each lens is 10 cm.

Two identical thin plano-convex glass lenses (refractive index 1.5) each having radius of curvature of 20 cm are placed with their convex surfaces in contact at the centre. The intervening space is filled with oil of refractive index 1.7. The focal length of the combination is

Which cleansing agent gets precipitated in hard water?

The phenomenon involved in the reflection of radio-waves by ionosphere is similar to

A toroid has 500 turns per metre length. If it carries a current of 2A, the magnetic energy density inside the toroid is

A thermodynamic system undergoes a cyclic process ABC as shown in the diagram. The work done by the system per cycle is

A Point object is moving uniformly towards the pole of a concave mirror of focal length 25 cm along its axis as shown below. The speed of the object is 1 $ms^{-1}$. At t = 0, the distance of the object from the mirror is 50 cm. The average velocity of the image formed by the mirror between time t = 0 and t = 0.25 s is

The brain capacity of Homo habilis

During inelastic collision between two bodies, which of the following quantities always remain conserved?

Ionized hydrogen atoms and $\alpha$-particles with same momenta enters perpendicular to a constant magnetic field. B. The ratio of their radii of their paths $r_H : r_\alpha$ will be :

Body A of mass 4m moving with speed u collides with another body B of mass 2m, at rest. The collision is head on and elastic in nature. After the collision the fraction of energy lost by the colliding body A is :

A force F = 20 + 10y action a particle in y-direction where F is in newton and y in meter. Work done by this force to move the particle from y = 0 to y = 1 m is :

When an unpolarised beam of light of intensity $I_0$ is incident on a polaroid, the intensity of transmitted light is

?Lumen? is the unit of

Two beams of red and violet colour are made to pass separately through a prism with angle of prism $60^{\circ}$. In the position of minimum deviation, the angle of refraction will be:

The molecules of which of the following gases has the highest speed?

Which of the following oxides would be reduced by C? ${Al_2 O_3, MgO, ZnO , CaO, Fe_2 O_3 , PbO} $

Let P be a $2 \times 2$ matrix such that [1 0] P = $ - \frac{1}{\sqrt{2}} [ 1 1]$ and $[0 1] P = \frac{1}{\sqrt{2}} [- 1 1]$ . If 0 and I denote the zero and identity matrices of order 2, respectively, then which of the following options is CORRECT ?

Nylon 66 is formed by

In which compound does H show O. N of -1?

If $A = \begin{bmatrix}\cos\alpha&\sin\alpha\\ - \sin\alpha&\cos\alpha\end{bmatrix}$ , then $AA' = $

1/log2100-1/log4100+1/log5100-1/log10100+1/log20100-1/log25100+1/log50100=?

A 20% ethanol solution is mixed with another ethanol solution, say, S of unknown concentration in the proportion 1:3 by volume. This mixture is then mixed with an equal volume of 20% ethanol solution. If the resultant mixture is a 31.25% ethanol solution, then the unknown concentration of S is

A chord of length 5 cm subtends an angle of 60° at the centre of a circle. The length, in cm, of a chord that subtends an angle of 120° at the centre of the same circle is

A jar contains a mixture of 175 ml water and 700 ml alcohol. Gopal takes out 10% of the mixture and substitutes it by water of the same amount. The process is repeated once again. The percentage of water in the mixture is now