Dual Nature of Radiation and Matter Test

Result

Dual Nature of Radiation and Matter Test - 27

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Weekly Quiz Competition

Question 1
4 / -1

U. V. light of wavelength 200 mm is incident on polished surface of Fe. work function of the surface is 4.5 eV. Find maximum speed of photo electrons.
(h = 6.625 × 10^–34 J.s, c = 3 × 10⁸ ms^–1. 1 eV = 1.6 × 10^–19)

A
7.75 × 10⁴ m/s

B
875 × 10⁵ m/s

C
8.75 × 10⁴ m/s

D
7.75 × 10⁵ m/s

Solution
Question 2
4 / -1

Light of 4560 Å 1 mW is incident on photo-sensitive surface of Cs (Cesium). If the quantum efficiency of the surface is 0.5% what is the amount of photoelectric current produced ?

A
1.84 mA

B
4.18 µA

C
4.18 mA

D
1.84 µA
Question 3
4 / -1

Work function of metal is 2 eV. Light of intensity 10^–5 Wm^–2 is incident on 2 cm² area of it. If 10¹⁷ electrons of these metals absorb the light, in how much time does the photo electric effect start ? Consider the waveform of incident light

A
1.4 × 10⁷ s

B
1.5 × 10⁷ s

C
1.6 × 10⁷ s

D
1.7 × 10⁷ s
Question 4
4 / -1

Radius of a beam of radiation of wavelength 5000 Å is 10^–3 m . Power of the beam is 10^–3 W . This beam is normally incident on a metal of work function 1.9 eV. The charge emitted by the metal per unit area in unit time is...............Assume that each incident photon emits one electron.
(h = 6.625 × 10^–34 J.s)

A
1.282 C

B
12.82 C

C
128.2 C

D
1282 C
Question 5
4 / -1

11 × 10¹¹ Photons are incident on a surface in 10 s. These photons correspond to a wavelength of 10 Å . If the surface area of the given surface is 0.01 m², the intensity of given radiations is...........
(h = 6.625 × 10^–34 J.s)

A
21.86 × 10^–3 W/m²

B
2.186 × 10^–3 W/m²

C
218.6 × 10^–3 W/m²

D
2186 × 10^–3 W/m²

Solution
Question 6
4 / -1

If alpha particle and neutron move with velocity v and 2v, the ratio of their de-Brogle wavelength will be.....................

A
1 : √2

B
2 : 1

C
1 : 1

D
√2 : 1

Solution
Question 7
4 / -1

Uncertainty in position of electron is found of the order of de-Broglie wavelength. Using Heisenberg\'s uncertainty principle, it is found that order of uncertainty in its velocity = ............

A
1v

B
2v

C
v/2π

D
2πv
Question 8
4 / -1

Frequency of incident light on body is f. Threshold frequency of body is f₀ . Maximum velocity of electron = ..................where m is mass of electron.

A

B

C

D
Question 9
4 / -1

If electron is accelerated under 50 KV in microscope, find its de-Broglie wavelength.

A
5.485 × 10^–12 m

B
8.545 × 10^–12 m

C
4.585 × 10^–12 m

D
5.845× 10^–12 m

Solution
Question 10
4 / -1

Energy of photon having wavelength is 2 eV. Maximum velocity of emitted photo electron after incidence of photon is v. If value of is decreased by 25% and maximum velocity is made double, work function metal will be.................eV

A
1.2

B
1.5

C
1.6

D
1.8