Physics Waves MDCAT 2019
PMDC Verified Question 100 of 125
The wavelength of the electromagnetic wave having frequency of 3 kHz will be?
A
80 km
B
100 km
C
140 km
D
120 km
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option B: 100 km
Concept:

All electromagnetic waves travel at the speed of light (\( c \)) in a vacuum.

Formula:

$$ c = f \lambda $$

Solution:

  • We know the speed of light is roughly \( c = 3 \times 10^8 \text{ m/s} \).


  • The given frequency is \( f = 3 \text{ kHz} = 3 \times 10^3 \text{ Hz} \).


  • Rearrange for wavelength: \( \lambda = \frac{c}{f} \).


  • \( \lambda = \frac{3 \times 10^8}{3 \times 10^3} = 1 \times 10^5 \text{ m} \).


  • Convert meters to kilometers: \( 10^5 \text{ m} = 100 \text{ km} \).


Why other options are incorrect:

Mathematical errors, such as forgetting the metric prefixes (kilo) or failing to divide correctly by powers of 10, lead to the other numbers.

Quality & Fidelity Assurance: Every question on BeambePrep is rigorously curated against the official PMDC syllabus with zero filler, zero out-of-syllabus content, and zero typos. When an authentic past paper originally contained a historical mistake or ambiguity from the examining board (such as UHS or NUMS), BeambePrep faithfully reflects the original paper while detailing the nuance and scientific consensus in the autopsy above.

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