Question

If 'FRIEND' is coded as 'HUMJTK', how is 'CANDLE' coded?

• A. EDRJRI
• B. EDQJRI
• C. EDSJRI
• D. EDRKRI

Hint:

In letter coding problems, carefully track the shift in alphabetical positions. Often the shift follows a consistent increasing or decreasing pattern.

Answer 1

The Correct Option is A

Step 1: Understanding the Question:
We need to determine the change in the magnetic field magnitude at the center of a circular loop when the number of turns \( n \) is modified, keeping the current \( I \) and radius \( R \) constant.
Step 2: Key Formula or Approach:
The magnetic field \( B \) at the center of a circular coil with \( n \) turns is given by:
\[ B = \frac{\mu_0 n I}{2R} \]
From this, we observe that \( B \propto n \) when \( I \) and \( R \) are constant.
Step 3: Detailed Explanation:
Initially, let the magnetic field be \( B_1 = \frac{\mu_0 n_1 I}{2R} \).
Given: \( n_2 = 2n_1 \) and current \( I \) remains the same.
The new magnetic field \( B_2 \) is:
\[ B_2 = \frac{\mu_0 (2n_1) I}{2R} \]
\[ B_2 = 2 \left( \frac{\mu_0 n_1 I}{2R} \right) \]
\[ B_2 = 2B_1 \]
Thus, the magnetic field is doubled.
Step 4: Final Answer:
The magnetic field becomes \( 2B \).