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# Test: Characteristics Of EM Waves

## 10 Questions MCQ Test Physics Class 12 | Test: Characteristics Of EM Waves

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This mock test of Test: Characteristics Of EM Waves for Class 12 helps you for every Class 12 entrance exam. This contains 10 Multiple Choice Questions for Class 12 Test: Characteristics Of EM Waves (mcq) to study with solutions a complete question bank. The solved questions answers in this Test: Characteristics Of EM Waves quiz give you a good mix of easy questions and tough questions. Class 12 students definitely take this Test: Characteristics Of EM Waves exercise for a better result in the exam. You can find other Test: Characteristics Of EM Waves extra questions, long questions & short questions for Class 12 on EduRev as well by searching above.
QUESTION: 1

### The speed of electromagnetic waves in free space is given by . Here μ0 is ___________and ε0 is ________________ of free space.

Solution:

μ0 is called the permeability of free space and similarly, ε0 is called the permittivity of free space.

QUESTION: 2

### Which region in the electromagnetic spectrum will have the highest speed?

Solution:

All regions have the same speed.
The speed of a wave is not dependent upon its frequency and wavelength but rather upon the properties of the medium through which it travels.

QUESTION: 3

### Which region in the electromagnetic spectrum has the highest frequency?

Solution:

A gamma ray or gamma radiation is a penetrating electromagnetic radiation arising from the radioactive decay of atomic nuclei. It consists of the shortest wavelength electromagnetic waves and so imparts the highest photon energy

QUESTION: 4

Electromagnetic waves constitute of

Solution:
QUESTION: 5

In electromagnetic waves the ratio of amplitudes of electric field and magnetic field is equal to​

Solution:

In electromagnetic waves the ratio of amplitudes of electric field and magnetic field is equal to the velocity of the electromagnetic waves in free space.

(E/ B0) = c

QUESTION: 6

Which statement is true about electromagnetic waves?

Solution:

Properties:• Electromagnetic waves are propagated by oscillating electric and magnetic fields oscillating at right angles to each other. Hence (a) is incorrect.
• Electromagnetic waves travel with a constant velocity of  3 x 108 ms-1 in vacuum. Hence (c) is incorrect.
• Electromagnetic waves need no medium of propagation. The energy from the sun is received by the earth through electromagnetic waves. Hence, correct answer is (b).

QUESTION: 7

Which of the following is not a use of electromagnetic wave?

Solution:

Electromagnetic waves are not used to determine global warming.

QUESTION: 8

Which colour of the visible spectrum has the greatest wavelength?

Solution:

Red light has the lowest energy and is least scattered and has thus least frequency, thus we get that it has the largest wavelength. Similarly violet has maximum frequency.

QUESTION: 9

The electric field for an em wave is: E = E0sin[(12 x 1015 t – 4 x 107 x)]. What is the speed of the em waves?​

Solution:
QUESTION: 10

The wavelength of X-rays is of the order of:

Solution:

X-ray wavelength is in range of 10−11m to 10−8m

So option C is correct.