Physics (Part-2) (CDS-Solved Paper)

Total Questions: 50

31. The outside rear view mirror of modern automobiles is marked with warning ‘objects in mirror are closer than they appear’. Such mirrors are [Morning Shift-2016 (I)]

Correct Answer: (d) convex mirrors
Solution:

The outside rear view mirror of modern automobiles are made up of convex mirror. So that, it can give wider field of view. Since, this type of mirror forms diminished, virtual image in between focus and pole of the mirror and smaller appearing objects seem farther away than they actually are. So, it is written that ‘objects in the mirror are closer than they appear’.

32. In respect of the difference of the gravitational force from electric and magnetic forces, which one of the following statements is true? [Morning Shift-2015 (I)]

Correct Answer: (b) Gravitational force is attractive only, whereas the electric and the magnetic forces are attractive as well as repulsive.
Solution:

As we know that, gravitational force is always attractive in nature and given by
Gm₁m₂/r²
where, G = gravitational constant. whereas electric force may be attractive or repulsive depending upon the nature of charge. Similarly, magnetic force is also attractive or repulsive depending on the nature of poles of the magnet.

33. Creation of something from nothing is against the law of [Morning Shift-2015 (I)]

Correct Answer: (b) conservation of mass-energy
Solution:

Every object in the universe possess mass. If there is no mass, then object does not exist. Also, as per law of conservation of energy, energy can neither be created nor be destroyed. It can only be transferred from one form to another.
Hence, creating of something from nothing is against conservation of mass-energy.

34. An electron and a proton are circulating with same speed in circular paths of equal radius. Which one among the following will happen, if the mass of a proton is about 2000 times that of an electron? [Morning Shift-2015 (I)]

Correct Answer: (b) The centripetal force required by the proton is about 2000 times more
Solution:

35. An object is raised to a height of 3 m from the ground. It is then allowed to fall on to a table 1 m high from ground level. In this context, which one among the following statements is correct? [Morning Shift-2015 (I)]

Correct Answer: (b) Its potential energy decreases by one-third of its original value of total energy
Solution:

36. Two pieces of conductor of same material and of equal length are connected in series with a cell. One of the two pieces has cross-sectional area double that of the other. Which one of the following statements is correct in this regard? [Morning Shift-2015 (I)]

Correct Answer: (a) The thicker one will allow stronger current to pass through it.
Solution:

37. The horizontal wind circulation near the earth’s surface is due to the [Morning Shift-2015 (I)]

1. pressure gradient
2. frictional force
3. coriolis force
Select the correct answer using the codes given below

Correct Answer: (d) All of these
Solution:

If the earth were stationary and had uniform surface, air would flow directly from high pressure to low pressure areas. Because none of these condition exist the direction and speed of wind are controlled by a number of factors.
These are pressure gradient, the coriolis effect, the centripetal acceleration and frictional force. Hence, option (d) is correct.

38. A wire bound standard resistor uses manganin or constantan. It is because [Morning Shift-2015 (I)]

Correct Answer: (d) they have resistivity which almost remains unchanged with temperature
Solution:

A wire bound standard resistor uses manganin or constantan because they have resistivity which is almost remaining unchanged with temperature.

39. According to the principle of conservation of momentum when the gun is fired, momentum of gun and bullet system remains constant. [Morning Shift-2015 (I)]

Statement I When a gun is fired, i.e. it pushes back with much less velocity than the velocity of the bullet.
Statement II Velocity of the recoiling gun is less because the gun is much heavier than bullet.
Codes

Correct Answer: (a) Both the statements are individually true and statement II is the correct explanation of statement I
Solution:

According to principle of conservation, when a bullet is fired from a gun, the gun exerts a force on the bullet in the forward direction. This is the action force. The bullet also exerts an equal force on the gun in the backward direction. This is the reaction force. Due to the large mass of the gun, it moves only, little distance backward by giving a jerk at the shoulder of the gun man. The backward movement of the gun is called the recoil of the gun. Heavier mass of gun has lesser velocity of recoil. Hence, code given in option (a) is correct.

40. In an observation, α-particles, β-particles and γ-rays have same energies. Their penetrating power in a given medium in increasing order will be [Morning Shift-2015 (I)]

Correct Answer: (a) α, β, γ
Solution:

The penetrating power is inversely proportional to mass and charge. Higher the mass and charge lesser will be penetrating power.α-particles contain higher mass and charge than β-particle. So, the correct order of penetrating power is α < β < γ