Which of the following statements is/are correct?

(a) Electromagnetic waves have different speeds in different mediums.

(b) Sounds have different speeds in different mediums.

Correct option is A

​$$\text{1. Statement (a): "Electromagnetic waves have different speeds in different mediums."} \\\text{Electromagnetic waves, such as light, radio waves, and microwaves, travel at different speeds in different mediums (e.g., air, water, or glass). The speed of electromagnetic waves is given by:} \\v = \frac{c}{n} \\\text{where:} \\\quad v \text{ is the speed of the wave in the medium,} \\\quad c \text{ is the speed of light in a vacuum } \left( c = 3 \times 10^8 \, \text{m/s} \right), \\\quad n \text{ is the refractive index of the medium.} \\\\\text{As the refractive index changes based on the medium, the speed of electromagnetic waves also changes. For example, light travels slower in water than in air due to the higher refractive index of water.}$$​$$\text{Statement (b): "Sounds have different speeds in different mediums."} \\\text{Sound waves also travel at different speeds in different mediums (solid, liquid, gas) because the speed of sound depends on the medium's properties, such as density and elasticity. The general formula for the speed of sound is:} \\v = \sqrt{\frac{B}{\rho}} \\\text{where:} \\\quad B \text{ is the bulk modulus (a measure of elasticity),} \\\quad \rho \text{ is the density of the medium.} \\\\\text{For example, sound travels faster in water than in air and even faster in steel or other solids due to the differences in density and elasticity.}$$​​