1 August 2021 (test 4)

Figure below shows a cold steel spoon in a cup of hot coffee. Which statement is correct when the spoon and the coffee are at thermal equilibrium?

• Temperature of the coffee is unchanged

• Temperature of the spoon is unchanged

• The coffee and spoon have the same temperature

• No heat flow between the coffee and the spoon

Figure above shows the length of the mercury thread in a thermometer when placed in ice and steam respectively. What is the temperature when the length of the mercury thread is 17.6cm?

• 37^oC

• 50.4^oC

• 63^oC

• 88^oC

Diagram above shows 20 g of milk at a temperature of 20^oC being mixed with 50 g of coffee at a temperature of 50^oC. What is the final temperature of the mixture?

• between 20^oC and 50^oC

• below 20^oC

• above 50^oC

Which of the following will increase the sensitivity of a mercury thermometer?

• Decrease the diameter of the capillary tube

• Increase the diameter of the capillary tube

• Decrease the length of the tube

• Increase the length of the tube

400 g of water at temperature 30^oC is added to X g of water at temperature of 100^oC. At thermal equilibrium, the temperature is 60^oC. What is the value of X?

• 300

• 400

• 800

• 933

760 J of heat is used to increase the temperature of 400 g of a copper block from 30^oC to 35^oC. What is the specific heat capacity of the copper block, in J kg^{-1 o}C^-1?

• 140

• 380

• 1200

• 4200

Why is the pot made of a low specific heat capacity material?

• To reduce the expansion of the pot

• To speed up the heating process

• To increase the melting pot

• To reduce the mass of the pot

What occurs during the melting of sulphur?

• Heat is released by the sulphur

• Temperature of the sulphur increases

• The bonding force between the sulphur molecules increases

• The kinetic energy of the sulphur molecules remain constant

A substance is heated and the temperature-time graph of the substance is shown below. At which portion is the substance absorbing latent heat?

• PQ and QR

• QR and ST

• RS and ST

• PQ and RS

Hot water at 100^oC is added to 100 g of ice cube at 0^oC. What is the minimum mass of hot water needed to melt all the ice cubes? [specific heat capacity of water= 4200 J kg^{-1 o}C^-1, specific latent heat of fusion of ice= 3.34x10⁵ J kg^-1]

• 13 g

• 40 g

• 80 g

• 126 g