Question

HELP ASAP VERY IMPORTANT.

1)Two jars are placed inside an insulated box. One jar contains ice water and the other contains hot soup. What will happen to the two liquids?
Both the hot soup and the ice water will lose heat
The hot soup will gain heat and the ice water will lose heat
The hot soup will lose heat and the ice water will gain heat.
Both the hot soup and the ice water will gain heat.

2)Why does conduction occur in solids and liquids easier compared to gases?



Because the particles in gases are closer together and move faster.


Because the particles in gases rarely move.


Because the particles in gases are closer together and move slower


Because the particles in gases are farther apart and move faster.

3)Bill and Mary wanted to have a snack after school. They heated some milk in a pot on the stove to make hot chocolate. They also popped some popcorn in the microwave oven. How did Bill and Mary transfer heat energy to make these snacks?



heating milk by radiation; popping popcorn by convection


heating milk by radiation; popping popcorn by radiation


heating milk by convection; popping popcorn by conduction


heating milk by conduction; popping popcorn by radiation

Answer 1

Answers:

1. The hot soup will loose the heat and the ice water will gain the heat

• If two jars are insulated inside the insulated box, the heat may not be transferred to outside of the box.

• According to II law of thermodynamics, Heat always flow from high temperature body to low temperature body, with out aid of external energy.

So, from two points, it is concluded that The hot soup will lose heat and the ice water will gain the heat until they reach the thermodynamic equilibrium.

2. The particles in gases are farther apart and move faster

• Particles in the gases are loosely packed (greater distance between particles compared to solids and liquids) and particles collide less often.

Therefore conduction is weak in gases compared to solids and liquids.

3. Heat and milk by conduction; popping popcorn by radiation.

• The heat can transfer from pot to the milk by conduction because they are in contact at boundaries, similarly the pot and the stove are in contact so the conduction transfers heat from pot to the milk.
• In microwave oven there is no direct contact (no conduction) of heat and popcorn, also there is no molecular momentum transfer (means of no convection).

So obviously the heat transfer by radiation occurs in a microwave oven.