Target Exam

CUET

Subject

Physics

Chapter

Electromagnetic Waves

Question:

A capacitor is connected in an electric circuit. When key is pressed, the energy density at a distance 3.5 m from the source will be (in joule/m3)

Options:

1.73 × 10–5

1.73 × 10–6

1.73 × 10–7

1.73 × 10–8

Correct Answer:

1.73 × 10–8

Explanation:

Energy density at 3.5 m is given by

u = $\frac{1}{2} \varepsilon_0 E_{m}^2$

$=\frac{1}{2} \times 8.85 \times 10^{-12} \times(62.6)^2$

= 1.73 × 10–8

Hence the correct answer will be (D)