The correct option is C. i.e. <span>Using more coils of wire
</span>
Explanation:
The strength of an electromagnet can be increased in the following ways:
1. By increasing the number of coils.
2. By increasing the current/voltage
3. Using an iron core, increases the strength of the electromagnet.
Answer:
The rate of heat conduction through the layer of still air is 517.4 W
Explanation:
Given:
Thickness of the still air layer (L) = 1 mm
Area of the still air = 1 m
Temperature of the still air ( T) = 20°C
Thermal conductivity of still air (K) at 20°C = 25.87mW/mK
Rate of heat conduction (Q) = ?
To determine the rate of heat conduction through the still air, we apply the formula below.


Q = 517.4 W
Therefore, the rate of heat conduction through the layer of still air is 517.4 W
The answer to your question is OPTION B