Tag: electromagnetic waves

Questions Related to electromagnetic waves

The working of a microwave oven involves 

physics electromagnetic waves properties and uses of different radiation electromagnetic spectrum spectrum

  1. Absorption of microwaves by matter

  2. Reception of microwaves by optical fibre

  3. Microwave amplification by stimulated emission of radiation

  4. Transmission of microwaves through a metal

Show answer
Correct Option: A
Explanation:

The working of microwave oven involves absorption of microwaves by matter.

The wavelength of $X$-rays is in the range

physics electromagnetic waves properties and uses of different radiation electromagnetic spectrum spectrum

  1. $0.001\mathring { A } $ to $1\mathring { A } $

  2. $0.001 nm$ to $1 nm$

  3. $0.001 \mu m$ to $1 \mu m$

  4. $0.001 cm $ to $1 cm$

Show answer
Correct Option: B
Explanation:

$X$-Rays Wavelength range $=1\times { 10 }^{ -11 }m$ to $3\times { 10 }^{ -8 }m$
So,                          $=0.001 nm$ to $1 nm$

Which of the following is correct for X-rays?

physics electromagnetic waves properties and uses of different radiation electromagnetic spectrum spectrum

  1. It has a beam of electrons

  2. It is electromagnetic waves

  3. It is positively charged particle

  4. It is negatively charged particles

Show answer
Correct Option: B
Explanation:

X-rays are electromagnetic waves with a wavelength less than about $10^{-9}$m. Cathode rays comprise of a beam of electrons. $\alpha$-rays are made up of helium nucleus(i.e., $^{4} _{2}He^{2+}$), hence are made up of positively charged particles, whereas $\beta$-rays are made up of energetic electrons, hence comprise of negatively charged particles.

Radio waves travel with a speed of.

physics electromagnetic waves properties and uses of different radiation electromagnetic spectrum spectrum

  1. $3\times 10^8$ m/sec

  2. $3\times 10^7$ m/sec

  3. $3\times 10^6$ m/sec

  4. $3\times 10^9$ m/sec

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Correct Option: A

If the distance that a radio wave can travel in the time of one complete cycle is $10$ metres, then the frequency of the radio wave in cycles per second is?

physics electromagnetic waves properties and uses of different radiation electromagnetic spectrum spectrum

  1. $3\times 10^9$Hz

  2. $3\times 10^6$Hz

  3. $3\times 10^8$Hz

  4. $3\times 10^7$Hz

Show answer
Correct Option: D

Study the frequency of the following electromagnetic radiations and select the correct relationship.
$1$. Infra red
$2$. Microwave
$3$. Ultra violet.

physics electromagnetic waves properties and uses of different radiation electromagnetic spectrum spectrum

  1. $3 > 2 > 1$

  2. $3 > 1 > 2$

  3. $1 > 2 > 3$

  4. $2 > 3 > 1$

Show answer
Correct Option: B

International broadcasting requires.

physics electromagnetic waves properties and uses of different radiation electromagnetic spectrum spectrum

  1. Medium frequency radio waves

  2. High frequency radio waves

  3. Low frequency radio waves

  4. Longitudinal waves

Show answer
Correct Option: B
Explanation:

International broadcasting requires high frequency radio waves which have high energy to travel over long distance.

A beam of electrons accelerated by a large potential difference $V$ is made to strike a metal target to produce $X-$rays. For which of the following values of $V$, the resulting $X-$rays have the lowest minimum wave length:

physics electromagnetic waves properties and uses of different radiation electromagnetic spectrum spectrum

  1. $10\ KV$

  2. $20\ KV$

  3. $30\ KV$

  4. $40\ KV$

Show answer
Correct Option: D
Explanation:

As we know, $\boxed{E _{max}=\dfrac{hc}{\lambda _{min}}}$

$\boxed{\lambda _{min}=\dfrac{hc}{ev}}$
Here the value of $v$ is given as $10kv,20kv,30kv,40kv$
A, $\boxed{\lambda \propto \dfrac{1}{V}}$, large value of $V$
$\Rightarrow$ min. value of $\lambda$
Hence for $40kv$, $\lambda _{min}$ is minimum.
$\therefore$ option $D$ is correct.

Radio isotope useful in treating blood cancer is

physics electromagnetic waves properties and uses of different radiation electromagnetic spectrum spectrum

  1. Cobalt 40

  2. Carbon 60

  3. Cobalt 60

  4. Carbon 14

Show answer
Correct Option: C
Explanation:

Cobalt therapy or cobalt $60$ therapy is the medical use of gamma rays from the radio isotope cobalt $-60$ to treat conditions such as cancer. Thus, Cobalt $-60$ is the radio isotope useful in treating the blood cancer.

The operating voltage in coolidge tube is ${10}^{5}V$. The speed of X-Rays produced is ________ $m{s}^{-1}$

physics electromagnetic waves properties and uses of different radiation electromagnetic spectrum spectrum

  1. $2\times { 10 }^{ 8 }\quad $

  2. ${ 10 }^{ 6 }$

  3. ${ 10 }^{ 5 }$

  4. $3\times { 10 }^{ 8 }$

Show answer
Correct Option: D
Explanation:

X-ray is an electromagnetic waves which moves with a speed equal to   $3\times 10^8 \ m/s$