Question

what is the wavelength of a 3*10^12 Hz infrared wave
A 3*10^20m
B 1* 10^4m
C 3*10^-3m
D 1*10^-4 m

Answer 1

Since, speed = frequency × wavelength

So,

3×10^8 = 3×10¹² × wavelength

So,

Wavelength =1 × 10-⁴

That is option (d).

Answer 2

Question: What is the wavelength of a 3 ×10 Hz infrared wave ?

Answer: Option (D) 1 × 10⁻⁴

We know that,

» Speed = frequency × wavelength

⇒ 3 × 10⁸ = 3 × 10¹² × wave length

⇒ Wavelength = 3 × 10⁸ / 3 × 10¹²

∴ Wavelength = 1 × 10⁻⁴