In case the antenna diameter in a radar system is increased to four times. The maximum range will be increased by:
A. 2 times
B. 4 times
C. 6 times
D. 8 times

Hint: This is the question from the communication systems chapter. In this question we have to consider the relation between the antenna diameter and the maximum range of the antenna. After finding the relation we have to check if diameter is increased by four times what will its impact be on the maximum range.

Complete step by step answer:
Radar uses radio waves to determine the various properties of a target such as range angle or velocity. It is mainly used to detect any kind of activity in restricted regions such as aircrafts and ships. Uses various kinds of antennas for the ranging. We have to consider the relation between the diameter of the antenna and the maximum range of the antenna.

The radius of the antenna is directly proportional to the bandwidth of the antenna and the bandwidth of the antenna is directly proportional to the maximum range of the antenna. Therefore, the radius of the antenna is directly proportional to the maximum range of the antenna and any change in the former will be the same in the latter. Therefore, if the diameter will be increased four times then the maximum range of them will also increase $four\ times.$

Hence, option B is correct.

Note:
Questions like these which are completely and purely textual seems like we have to use the mathematical equation to solve but we have to visualize and understand the relation between the two parameters and if the relation is directly or inversely proportional we can calculate the answer without any calculation which will be much more faster than using the relation and putting the actual values.