Question

33.1 electromagnetic waves
the time for a radar signal to travel to the moon and back, a one - way distance of about 3.8×10⁸ m, is
1×10⁶ s
8.3 s
1.3 s
8.3 min
2.5 s

Explanation:

Step1: Calculate the total distance

The radar signal travels to the Moon and back. The one - way distance \(d = 3.8\times10^{8}\text{ m}\), so the total distance \(D=2d = 2\times3.8\times 10^{8}\text{ m}=7.6\times10^{8}\text{ m}\)

Step2: Use the formula \(v=\frac{D}{t}\) (where \(v = c=3\times10^{8}\text{ m/s}\) for electromagnetic waves)

We can solve for \(t\), \(t=\frac{D}{v}\). Substitute \(D = 7.6\times10^{8}\text{ m}\) and \(v = 3\times10^{8}\text{ m/s}\) into the formula: \(t=\frac{7.6\times 10^{8}}{3\times10^{8}}\text{ s}\approx2.5\text{ s}\)

Answer:

\(2.5\text{ s}\)