Question

The field inside a solenoid is …….
(A) Directly proportional to its length.
(B) Directly proportional to current.
(C) Inversely proportional to number of turns.
(D) Inversely proportional to current.

Answer 1

Hint: For solving this equation, we must have the knowledge about Solenoid. A coil of wire which acts as an electromagnet when electricity passes through it, is termed as a Solenoid. Electromagnetic solenoids find uses all over the world. A magnet field is produced around a solenoid when a current is passed through it.

Complete step by step answer:
Importance of Solenoid:-
-Solenoid creates a magnetic field which is useful in controlling locks, water pressure, air pressure etc.
-A solenoid is commonly used in automatic locking mechanisms.
-Solenoid is also very important in the medical field.
-It is an essential component for dialysis machines.
-Inside a solenoid the magnetic field is directly proportional to both the applied current and the number of turns per unit length. The field inside the solenoid is constant.
Now, we will solve the given question.
Since, we know that the magnetic field inside a solenoid is given by –
 $B = {\mu _0}nI$
Therefore, B is directly proportional to I.
Hence, the correct answer is B, which is that inside a solenoid the field is directly proportional to the current flowing through it.

Note:
Solenoids are important as they can create controlled magnetic fields which can be used as electromagnets. A solenoid is a very important coil of wire which is used in electromagnets, antennas, inductors, valves, and many more.