(i) What mass of ice at 0°C added to 2.1 kg water, will cool it down from 75°C to 25°C?

Given Specific heat capacity of water = 4.2 Jg-1 o C-1 ,

Specific latent heat of ice = 336 jg-1

(ii) The diagram below shows a cooling curve for a substance:
(a) State the temperatures at which the substance condenses.
(b) The temperature range in which the substance is in liquid state.




(c) Why do we prefer ice to ice-cold water for cooling a drink?

(iii) A magnet is released along the axis of a copper coil as shown in the diagram.



(a) State the polarity at the top end of the coil when the magnet leaves the coil.
(b) The direction of the current is from A to B when magnet enters the coil. What will be the direction of the current when the magnet leaves the coil.
(c) Name the law which can be used to determine the direction of the induced current in the coil?
(d) State one way to increase the magnitude of the induced current in the coil?

Solution

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