Answer: vertical arrow downwards

Sub-topic Code: P4.1 (Thermal Properties)

Detailed Solution: The cooled air moves downwards due to its higher density compared to the warmer air in the refrigerator.

Answer: solid has regular arrangement / liquid has irregular arrangement; particles are further apart in a liquid

Sub-topic Code: P4.1 (States of Matter)

Detailed Solution: In a solid, particles are arranged in a regular, fixed pattern, while in a liquid, the arrangement is irregular. Additionally, particles in a liquid are further apart compared to those in a solid.

Answer: \( R = \frac{V}{I} = \frac{240}{0.04} = 6000 \, \Omega \)

Sub-topic Code: P9.1 (Electric Circuits)

Detailed Solution: Using Ohm’s Law, \( R = \frac{V}{I} \), where \( V = 240 \, V \) and \( I = 0.04 \, A \). Thus, \( R = \frac{240}{0.04} = 6000 \, \Omega \).

Answer: 3000 Ω; combined resistance of two resistors in parallel is less than that of either resistor by itself

Sub-topic Code: P9.1 (Electric Circuits)

Detailed Solution: When two resistors of equal resistance (6000 Ω) are connected in parallel, the combined resistance is half of one resistor, i.e., 3000 Ω. This is because the total resistance in parallel is always less than the smallest individual resistance.

Answer: increase current; increase number of turns on coil

Sub-topic Code: P11.1 (Electromagnetism)

Detailed Solution: The turning effect of a motor can be increased by increasing the current flowing through the coil or by increasing the number of turns on the coil, which increases the magnetic field strength.