18. Which does not affect the strength of an electromagnet?
A the current in the solenoid
B the temperature of the coil
OC the number of loops in the coil
D the type of ferromagnetic core

sonar - device which is used to find the submit submarines, sankalp ship. sonar waves consists of a transmitter and detector which are installed in the observation centre on board of a ship. the ultrasonic waves are sent into the sea at high frequency about 1000 khz in all direction.

1 is a answer of a question