CUET · PHYSICS · PYQ PAPER 2023

The electric field intensity produced by the radiations coming from a 200 W bulb at 6 m distance is E . What is the electric field intensity produced by the radiations coming from 100 W bulb at the same distance?

A \(\frac{E}{\sqrt{2}}\)
B \(0.5 E\)
C \(E \sqrt{2}\)
D \(2 E\)

Verified Solution

Answer & Solution

Correct Answer

(A) \(\frac{E}{\sqrt{2}}\)

Step-by-step Solution

Detailed explanation

\(E \propto \sqrt{P}\) \(\frac{E_{new}}{E} = \sqrt{\frac{P_{new}}{P_{old}}}\) \(E_{new} = E \sqrt{\frac{100\, \text{W}}{200\, \text{W}}} = E \sqrt{\frac{1}{2}}\) \(E_{new} = \frac{E}{\sqrt{2}}\)

Apply the relevant identity from the chapter and substitute the values established in the previous step, keeping the original constraint in view.

Use the simplified expression to isolate the unknown, then plug the result back into the question setup to confirm the working is internally consistent.

Cross-check against a boundary or limiting case. Both the dimensional balance and the qualitative behaviour at the extreme should agree with the candidate answer.

Combine the steps above to identify the correct option. The remaining choices each fail at least one of the consistency, dimensional, or boundary checks.

Same subject

Match List-I with List-II

List-I	List-II
(A) Magnifying power of a simple microscope	(I) \( \frac{L}{f_o} \times \frac{D}{f_e} \)
(B) Magnifying power of a compound microscope	(II) \( \frac{f_o}{f_e} \left(1 + \frac{f_e}{D}\right) \)
(C) Magnifying power of a telescope (normal adjustment)	(III) \( 1 + \frac{D}{f_e} \)
(D) Magnifying power of a telescope when final image is formed at least distance of distinct vision	(IV) \( \frac{f_o}{f_e} \)

Choose the correct answer from the options given below:

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