TS EAMCET · Physics · Electromagnetic Waves
A laser beam is operating at \(100 \mathrm{~mW}\). The amount of energy stored by \(90 \mathrm{~cm}\) length of this laser beam will be
- A \(2 \times 10^{-10} \mathrm{~J}\)
- B \(3 \times 10^{-10} \mathrm{~J}\)
- C \(8 \times 10^{-11} \mathrm{~J}\)
- D \(6 \times 10^{-11} \mathrm{~J}\)
Answer & Solution
Correct Answer
(B) \(3 \times 10^{-10} \mathrm{~J}\)
Step-by-step Solution
Detailed explanation
Energy of LASER beam, \(=\frac{I l}{C}=\frac{100 \times 10^{-3} \times 90 \times 10^{-2}}{3 \times 10^8}=3 \times 10^{-10} \mathrm{~J}\)
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