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CUET · PHYSICS · PYQ PAPER 2023

A vertical electric field of magnitude \( 4.9 \times 10^5 \text{ NC}^{-1} \) just prevents a water droplet of mass \( 0.1 \text{ g} \) from falling. What is the charge on the droplet? Take acceleration due to gravity \( 9.8 \text{ ms}^{-2} \).

  1. A \( 2.0 \times 10^{-9} \text{ C} \)
  2. B \( 2.0 \times 10^{-6} \text{ C} \)
  3. C \( 5.0 \times 10^5 \text{ C} \)
  4. D \( 5.0 \times 10^6 \text{ C} \)
Verified Solution

Answer & Solution

Correct Answer

(A) \( 2.0 \times 10^{-9} \text{ C} \)

Step-by-step Solution

Detailed explanation

\( F_e = F_g \) \( qE = mg \) \( q = \frac{mg}{E} \) \( q = \frac{(0.1 \times 10^{-3} \text{ kg})(9.8 \text{ ms}^{-2})}{4.9 \times 10^5 \text{ NC}^{-1}} \) \( q = 2.0 \times 10^{-9} \text{ C} \)