set 7 MCQ Questions & Answers Detailed Explanation

Question : 1

Expansion during heating

a) Increases the weight of the material

b) Decreases the density of the material

c) Occurs only in solid

d) Occurs at the same rate for all liquids and solids

Question : 2

Two pulses travel in mutually opposite directions in a string with a speed of 2.5 cm/s as shown in the figure. Initially the pulses are 10 cm apart. What will be the state of the string after two seconds

a)

b)

c)

d)

Question : 3

The surface of a lake is frozen in severe winter, but the water at its bottom is still liquid. What is the reason ?

a) The density of water is maximum at 4°C.

b) Since the surface of the lake is at the same temperature as the air, no heat is lost.

c) Ice is a bad conductor of heat.

d) None

Question : 4

Match List I with List II and select the correct answer using the codes given below the lists.

a) A – 4, B – 1, C – 2, D – 3

b) A – 2, B – 1, C – 4, D – 3

c) A – 2, B – 3, C – 4, D – 1

d) A – 4, B – 3, C – 2, D – 1

Question : 5

Reading glasses are made from which type of lenses?

a) Plain

b) Convex

c) Concave

d) None of these

Question : 6

Consider the following statements :

1. Convex lens is used ina  terrestrial telescope.
2. Convex lens of a small focal length is used as a magnifying glass.
3. Convex lens forms an enlarged image of an object, when the object is placed beyond the focus of the lens.

a) 1 and 3

b) 1 and 2

c) 2 and 3

d) 1, 2 and 3