Which mode of heat transfer primarily occurs in solids due to the vibration of particles?

A. Convection

B. Radiation

C. Conduction

D. Reflection

Which of the following is NOT a greenhouse gas?

A. Carbon dioxide

B. Methane

C. Nitrogen

D. Water vapour

In which medium does convection primarily occur?

A. Solids

B. Liquids

C. Gases

D. Both B and C

Which property determines the amount of energy radiated by a black body in terms of its temperature?

A. Stefan's Law

B. Newton's Law

C. Ohm's Law

D. Boyle's Law

Which factor does NOT affect the rate of conduction in a material?

A. Temperature difference

B. Material's state

C. Cross-sectional area

D. Colour of the material

a) Explain the process of conduction and how it results in heat transfer in solids. [3]

b) A metal rod of length 1.5m and cross-sectional area 0.002 m^2 has a temperature difference of 20°C between its ends. If the thermal conductivity of the metal is 400 W/(m·K), calculate the rate of heat transfer through the rod. [3]

a) Describe the mechanism of convection currents in fluids and their significance in various natural phenomena. [3]

b) A container has water heated from below. If the temperature difference between the bottom and top of the container is 25°C and the height of the water column is 0.5m, calculate the change in density of the water due to this temperature difference. (Assume the volume expansion coefficient of water is 0.000214 1/°C) [3]

a) Explain the concept of electromagnetic radiation as a mode of heat transfer. [3]

b) An object at a temperature of 500K emits radiation with a peak wavelength of 5.8 x 10^-6 m. Using Wien's displacement law, calculate the constant. [3]

a) Describe the factors that affect the rate of heat transfer through conduction in solids. [3]

b) A copper rod and an aluminium rod of the same dimensions are placed end to end. If the copper rod conducts heat at a rate of 400 W and the aluminium rod conducts heat at a rate of 200 W, which rod will have a higher temperature gradient? [2]

c) How does the temperature gradient relate to the rate of heat transfer in solids? [2]

a) Explain the principle behind the formation of convection currents in the Earth's mantle. [3]

b) How do convection currents in the Earth's mantle influence tectonic plate movements? [3]

c) Why are convection currents more prominent in fluids compared to solids? [2]

What is the primary mechanism behind the greenhouse effect?

A. Absorption of UV rays by the Earth's surface

B. Reflection of solar radiation by clouds

C. Absorption and re-emission of infrared radiation by greenhouse gases

D. Conduction of heat in the atmosphere

Which of the following materials would have the highest thermal conductivity?

A. Wood

B. Glass

C. Copper

D. Rubber

Which mode of heat transfer does NOT require a medium?

A. Conduction

B. Convection

C. Radiation

D. Reflection

What is the primary challenge associated with harnessing geothermal energy?

A. Limited to specific regions

B. Production of greenhouse gases

C. Requires large land areas

D. Limited to daytime

Which of the following best describes the role of greenhouse gases in the Earth's atmosphere?

A. They reflect all solar radiation.

B. They allow solar radiation to pass through but trap infrared radiation.

C. They absorb all forms of radiation.

D. They only allow infrared radiation to pass through.

a) Describe the properties of electromagnetic radiation that make it suitable for heat transfer. [3]

b) An object emits radiation with a peak wavelength of 2 x 10^-6 m. Using Wien's displacement law, calculate its temperature. [3]

c) How does the intensity of radiation emitted by an object change with its temperature? [2]

a) What is the greenhouse effect and how does it impact the Earth's climate? [3]

b) List three major greenhouse gases and their sources. [3]

c) How does the increase in greenhouse gases lead to global warming? [2]

a) Explain the mechanism of heat transfer in solids through conduction. [3]

b) A metal rod of length 1 m and cross-sectional area 0.01 m^2 has a temperature difference of 20°C between its ends. If the thermal conductivity of the metal is 400 W/(m·K), calculate the rate of heat transfer through the rod. [3]

c) How does increasing the length of the rod affect the rate of heat transfer? [2]

d) Name two real-world applications where good conductors of heat are essential. [2]

a) Describe the formation of convection currents in water when heated from below. [3]

b) How do these convection currents differ in viscous liquids compared to water? [3]

c) Explain the significance of convection currents in the Earth's atmosphere. [3]

d) Why is convection not observed in solids? [2]

a) What is electromagnetic radiation, and how is it related to heat transfer? [3]

b) An object at a temperature of 5000 K emits radiation with a peak wavelength. Using Wien's displacement law, calculate the peak wavelength. [3]

c) How does the intensity of radiation emitted by an object change with an increase in its temperature? [3]

d) Why are objects that are good absorbers of radiation also good emitters? [2]