Nature of Electromagnetic Radiation

Q.

The frequency of yellow light having wavelength 600 nm is

1. $5.0\times {10}^{14}Hz$

2. $2.5\times {10}^{7}Hz$

3. $5.0\times {10}^{7}Hz$

4. $2.5\times {10}^{14}Hz$

Q.

The de-Broglie wavelength of a particle with mass 1gm and velocity 100m/sec is

1. 6.63 × 10^-33 m

2. 6.63 × 10^-34 m

3. 6.63 × 10^-35 m

4. 6.65 × 10^-35 m

Q.

In vacuum all types of electromagnetic radiations, regardless of wavelength, travel at the same speed.

1. True

2. False

Q.

In hydrogen atom the kinetic energy of electron is 3.4 eV. The distance of that electron from the nucleus:

1. 1.587A⁰

2. 0.529A⁰

3. 2.116A⁰

4. 21.16A⁰

Q. The ratio of energies of two photons of wavelengths $2000A^{\circ }$ and $4000A^{\circ }$.

1. 1:4

2. 4:1

3. 1:2

4. 2:1

Q. The correct sequence of frequency for electromagnetic radiations in the electromagnetic spectrum is:

1. X-rays > UV rays > Microwaves > Radio waves
2. Radio waves > Microwaves > UV rays > X-rays
3. UV rays > X-rays > Radio waves > Microwaves
4. Radio waves > Microwaves > X-rays > UV rays

Q.

Visible spectrum is 400 mm to 750 nm.

1. True

2. False

Q.

Wavenumber is defined as the number of wavelengths per unit length

1. True

2. False

Q. Which of the following statements are incorrect regarding properties of EM waves?

1. Electric and magnetic field components oscillate perpendicular to each other and to the direction of propagation of the wave.
2. EM waves cannot travel in vacuum and require a medium
3. When an electrically charged particle moves under acceleration, electric and magnetic fields are produced
4. None of these

Q.

Frequency is defined as the distance between two neighbouring crests or troughs of a wave.

1. True

2. False

Q.

A photon of 300 nm is absorbed by a gas, which then re-emits two photons. One re-emitted photon has a wavelength of 400 nm. Calculate the energy of the other photon re-emitted out.

1. 16.56 x 10^-18 J

2. 16.56 x 10^-12 J

3. 16.56 x 10^-20 J

4. 16.56 x 10^-15 J

Q. On absorbing light of wavelength 3800 \overset0A bromine molecule undergoes dissociation and forms atoms, The kinetic energy of one bromine atom assuming that one quantum of radiation is absorbed by each molecule would be ( Bond energy of Br_2=190 kJ/mol) (1) 1.04×10^{-19} J (2) 2.08×10^{-19} J (3) 1.25×10^{-5} J (4) 6.25×10^{-4} J

Q.

If a source is transmitting an electromagnetic wave of frequency $8.2\times {10}^{6}Hz$, then the wavelength of the electro-magnetic waves transmitted from the source will be

1. $36.6m$

2. $40.5m$

3. $42.3m$

4. $50.9m$

Q. An electron in unielectronic species A+x is present in nth orbit. The separation energy of that electron from nth orbit is 7.65 eV. The frequency of photon required to excite electron from nth orbit to (n + 2)th orbit is 1.025 × 1015 Hz. Mark the correct statement. a)The value of (n + 1) is 4 b) Element A is Beryllium c) Value of x is 2 d)Kinetic energy of electron in (n + 2) orbit is 1.51 eV

Q. What electronic transition in the $H{e}^{+}$ ion would emit the radiation of the same wavelength as that of the first Lyman transition of hydrogen atom ?

1. $2\to 1$
2. $4\to 2$
3. $3\to 1$
4. $2\to 4$

Q.

The de-Brogile wavelength of an electron moving in a circular orbit is $\lambda$. The minimum radius of orbit is

1. 

2. 

3. 

4. 

Q.

Calculate (a) wavenumber and (b) frequency of yellow radiation having wavelength 5800 $\mathring{A}$.

1. $1.724\times {10}^{4}c{m}^{-1}and5.172\times {10}^{12}{s}^{-1}$

2. $1.724\times {10}^{4}c{m}^{-1}and5.172\times {10}^{14}{s}^{-1}$

3. $1.724\times {10}^{12}c{m}^{-1}and5.172\times {10}^4{s}^{-1}$

4. $1.724\times {10}^{12}c{m}^{-1}and5.172\times {10}^2{s}^{-1}$

Q.

The wavelength range of the visible spectrum extends from violet (400 nm) to red (750 nm). Express these wavelength in frequencies (Hz). $(1nm={10}^{-9}m)$.

1. $4\times {10}^{14}to7.5\times {10}^{14}Hz$

2. $8\times {10}^{14}to16\times {10}^{14}Hz$

3. $7\times {10}^{14}to16\times {10}^{14}Hz$

4. $7.5\times {10}^{14}to16\times {10}^{14}Hz$

Q. The MRI (Magnetic Resonance Imaging) body scanners used in hospitals operate with $400M{H}_Z$ radio frequency. The wavelength corresponding to this radio frequency is:

1. 0.75 m
2. 0.75 cm
3. 1.5 m
4. 2 cm

Q. Which of the following statements is incorrect regarding wave theory:

1. The distance between successive peaks and troughs is called wavelength
2. These waves consist of electric and magnetic fields perpendicular to each other and are perpendicular to the direction of propagation of the radiation
3. Electromagnetic radiation travels with a velocity of $3\times {10}^8$ m/s
4. Electromagnetic waves do not require any medium for propagation

Q.

Arrange the following type of radiations in increasing order of frequency: (a) radiation from microwave oven (b) amber light from traffic signal (c) radiation from FM radio (d) cosmic rays from outer space and (e) X-rays.

Q. The longest wavelength line in Lyman series of hydrogen atom spectrum will be
($R_H=$ Rydberg constant)

1. $\frac{3R_H}{4}$
2. $\frac{4}{R_H}$
3. $\frac{1}{R_H}$
4. $\frac{4}{3R_H}$

Q.

what is the difference between matter waves and electromagnetic waves ??

Q. Find the frequency range of visible light, given that it encompasses wavelengths from 380 nm to 760 nm.

1. $3.95\times {10}^{14}{\text{s}}^{-1}\to 7.89\times {10}^{14}{\text{s}}^{-1}$
2. $3.95\times {10}^{17}{\text{s}}^{-1}\to 7.89\times {10}^{17}{\text{s}}^{-1}$
3. $2.95\times {10}^{14}{\text{s}}^{-1}\to 7.89\times {10}^{14}{\text{s}}^{-1}$
4. $2.95\times {10}^{17}{\text{s}}^{-1}\to 7.89\times {10}^{17}{\text{s}}^{-1}$

Q. Why exchange energy always takes place between the electrons of same spin?

Q. 52. If K.E of an electron , alpha particle and a photon are represented by E1, E2 and E3 respectively(provided all these have same de Broglie wavelength) then 1-E1=E2=E3 2-E1>E3>E2

Q. The electromagnetic radiation of maximum frequency among the following is

1. $\gamma$ rays
2. X rays
3. Microwave
4. UV rays

Q. Arrange the following type of radiations in increasing order of frequency: (a) radiation from microwave oven (b) amber light from traffic signal (c) radiation from FM radio (d) cosmic rays from outer space and (e) X-rays.

Q. Correct order of frequency of the given electromagnetic radiation is

1. $\text{Microwave > IR > Radio waves}$
2. $\text{IR > Microwave > Radio waves}$
3. $\text{Radio waves > Microwave > IR}$
4. $\text{Radio waves > IR > Microwave}$

Q.

Arrangethe following type of radiations in increasing order of frequency:(a) radiation from microwave oven (b) amberlight from traffic signal (c) radiation from FM radio (d) cosmic raysfrom outer space and (e) X-rays.