Question

Pick correct statement(s) from the following:
(a) Electric field and Magnetic field are basically independent
(b) Electric field and Magnetic field are two aspects of the electromagnetic field
(c) Electric field and Magnetic field may be produced by charge at rest
(d) A moving charge produces both Electric and Magnetic Fields

(A) a and b are correct
(B) b and d are correct
(C) b, c and d are correct
(D) a, c and d are correct

Answer 1

Hint: To check which of the given options are correct, we see whether a relation between Electric Field and magnetic field exists or not. This will tell us whether they are dependent or independent from each other. We will also check the field properties of a charge at rest and a moving charge. This will help us in solving the other parts of the given question.

Complete answer:
For the first part of the problem, we have to state whether Electric field and magnetic field are independent or not.
We know that if a time varying Electric field is given by E then it produces a time varying Magnetic field which is given by:
$\Rightarrow B=\dfrac{E}{c}$
Where,
$c$ is the speed of light under given conditions.
The existence of this relation proves that Electric field and Magnetic field are not independent but rely on each other.
Thus, statement (a) is incorrect.
Now, as we know that, Electric field and Magnetic field are two aspects of the same thing, because a changing Electric field produces a changing Magnetic field and vice versa. This is the reason why we refer to them together as Electromagnetism.
Thus, statement (b) is the correct statement.
Now for the third and fourth statement, we know the fact that a stationary charge only produces an Electric field. On the other hand, a moving charge produces an Electric field as well as a Magnetic field.
This means that statement (c) is incorrect whereas statement (d) is correct.
Hence, statement (b) and statement (d) are the correct statements.

Hence, option (B) is the correct option.

Note:
We should always know the basic properties of Electric and Magnetic fields, like how they are produced, the effects on them under different circumstances and conditions, etc. Conceptual based questions are easy and quick to solve, only if one has an in-depth knowledge of the topic.