In a mercury thermometer, the level of mercury rises when its bulb comes in contact with a hot object. What is the reason for this rise in the level of mercury?

2

(a)

Shopkeepers selling ice blocks usually cover them with jute sacks. Explain why.

2

(a)

The radiators in cars are painted black. Explain why.

2

(a)

While constructing a house in a coastal area, in which direction should the windows preferably face and why?

2

(a)

Name the mode of transfer of heat in which medium is not required.

2

(a)

It is preferred to use two thin blankets rather than one thick blanket. Explain the reason.

2

(a)

Why is it advised not to hold the thermometer by its bulb while reading it?

2

(a)

You may have noticed that a few sharp jerks are given to clinical thermometer before using it. Why is it done so?

2

(a)

Why convection is not possible in solids?

2

(a)

Distinguish between clinical and laboratory thermometer.

2

(a)

How are the lower and upper scale of a thermometer fixed?

2

(a)

Give a make up of clinical thermometer.

2

(a)

It is observed that two thin woollen blankets are warmer than a thick woollen blanket. Comment.

2

(a)

We wear light coloured clothes in summer and dark coloured clothes in winter. Comment.

2

(a)

Which will cool faster-water kept in a black pot or kept in silver pot?

2

(a)