Question

Suppose a British official tried transmitting electricity generated from London to New Delhi in ${17}^{th}$ century when India had no access to electricity. Taking the distance between London & New Delhi approximately as 7000 km, find out the time taken to transmit electricity (assume a metal conductor for transmission).

• A. 0.1 s
• B. 0.023 s
• C. 2.3 s
• D. Electricity cannot be transmitted over such long distances

Answer 1

The correct option is B 0.023 s

We know that in a material, electricity travels at a speed of light, c =$3\times {10}^8$ m/s.

We also know that, $Speed=\frac{Distance}{Time}$

$⟹Time=\frac{Distance}{Speed}$

Distance in metre = $7\times {10}^6$ m

∴ Time = $\frac{7000000}{300000000}$ sec

Hence, time taken for transmission of electricity from London to New Delhi will be 0.023 sec.