Physics is Easy

Find the capacitance

Questions of the day

An electromagnetic wave enters a medium of lower refractive index.
Three statements are made:
I The wavelength of the wave has increased.
II The frequency of the wave has decreased.
III. The speed of the wave has increased.

What is true about the properties of the wave?

A

I and II only

B

I and III only

C

II and III only

D

I, II and III

Type your answer in comment

Which of the following is not one of the seven basic SI units?
ampere
kilogram
kelvin
feet

Solution

Seven basic SI units are
kg,s,Ampere,kelvin, mole,candela,metre

Feet is not SI unit
Option 4 is correct

Shout out to my newest followers! Excited to have you onboard! সোহেল মোল্লা খামারী, Dok Saligan

Question: 6. An electromagnetic wave enters a medium of lower refractive index.Three statements are made
1. The wavelength of the wave has increased.
II. The frequency of the wave has decreased.
III. The speed of the wave has increased.
What is true about the properties of the wave
A. I and II only
B. I and III only
C. II and III only
D. I, II and III

Explanation

When an electromagnetic wave enters a medium of lower refractive index (n decreases):

V=c/n

Speed (v) of light increases, because

Lower n → higher v

Frequency (f) of light does NOT change when light goes from one medium to another.

Frequency is decided by the source, not the medium.

Wavelength (λ) changes according to

Since speed increases and frequency remains constant, wavelength increases.

Now check the statements:

I. Wavelength has increased ✅ True
II. Frequency has decreased ❌ False
III. Speed has increased ✅ True

Correct answer:

B. I and III only ✔️