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TN 12th Computer Applications மின்னணு தரவு பரிமாற்றம் Sample Question Papers Study Material - QB365 Set A

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TN 12th Computer Applications மின் - வணிக பாதுகாப்பு அமைப்புகள் Sample Question Papers Study Material - QB365 Set A

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TN 12th Computer Applications மின்னணு செலுத்தல் முறைகள் Sample Question Papers Study Material - QB365 Set A

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TN 12th Computer Applications மின் - வணிகம் Sample Question Papers Study Material - QB365 Set A

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TN 12th Computer Applications திறந்த மூல கருத்துருக்கள் Sample Question Papers Study Material - QB365 Set A

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TN 12th Computer Applications வலையமைப்பு வடமிடல் Sample Question Papers Study Material - QB365 Set A

12th Standard English Medium Physics Subject Dual Nature of Radiation and Matter Book Back 1 Mark Questions with Solution Part - II updated Book back Questions

Published on: 13/05/2022

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Std: 12th Standard - Physics

chapter: - Book back Questions

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Questions:

Multiple Choice Question

5 x 1 = 5

Emission of electrons by the absorption of heat energy is called ______ emission.

(a)

photoelectric

(b)

field

(c)

thermionic

(d)

secondary

Photons of wavelength λ are incident on a metal. The most energetic electrons ejected from the metal are bent into a circular arc of radius R by a perpendicular magnetic field having magnitude B. The work function of the metal is _____.

(a)

\(\frac { hc }{ \lambda } -{ m }_{ e }+\frac { e^{ 2 }{ B }^{ 2 }{ R }^{ 2 } }{ { 2m }_{ e } } \)

(b)

\(\frac { hc }{ \lambda } +{ 2m }_{ e }{ \left[ \frac { eBR }{ { 2m }_{ e } } \right] }^{ 2 }\)

(c)

\(\\ \frac { hc }{ \lambda } -{ m }_{ e }{ c }^{ 2 }-\frac { e^{ 2 }{ B }^{ 2 }{ R }^{ 2 } }{ { 2m }_{ e } } \)

(d)

\(\frac { hc }{ \lambda } -{ 2m }_{ e }{ \left[ \frac { eBR }{ { 2m }_{ e } } \right] }^{ 2 }\)

The threshold wavelength for a metal surface whose photoelectric work function is 3.313 eV is _____.

(a)

4125 \(\mathring { A } \)

(b)

3750\(\mathring { A } \)

(c)

6000\(\mathring { A } \)

(d)

2062.5\(\mathring { A } \)

A light source of wavelength 520 nm emits 1.04 x 10¹⁵photons per second while the second source of 460 nm produces 1.38 x 10¹⁵ photons per second. Then the ratio of power of second source to that of first source is _____.

(a)

1.00

(b)

1.02

(c)

1.5

(d)

0.98

In photoelectric emission, a radiation whose frequency is 4 times threshold frequency of a certain metal is incident on the metal. Then the maximum possible velocity of the emitted electron will be _____.

(a)

\(\sqrt { \frac { { hv }_{ o } }{ m } } \)

(b)

\(\sqrt { \frac { { 6hv }_{ o } }{ m } } \)

(c)

\(2\sqrt { \frac { { hv }_{ o } }{ m } } \)

(d)

\(\sqrt { \frac { { hv }_{ o } }{2m } } \)

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Answers Key:

Multiple Choice Question

5 x 1 = 5

\(\text {K.E } =\frac{B^2 q^2 r^2}{2 m} \)
\(\phi =\frac{h c}{\lambda}-K . E \)
\(=\frac{h c}{\lambda}-\frac{B^2 q^2 r^2}{2 m} \)
\(\phi =\frac{h c}{\lambda}-2 m\left(\frac{B q r}{2 m}\right)^2\)

\(\lambda_0 =\frac{h c}{\phi} \)
\(=\frac{6.626 \times 10^{-34} \times 3 \times 10^8}{3.313 \times 1.6 \times 10^{-19}} \)
\( =\frac{19.8782400}{5.3} \times 10^{-7} \)
\(\lambda_0 =3.750 \times 10^{-7} \simeq 3750 \stackrel{o}A\)

\(P =\frac{E}{t}=\frac{n h v}{t}=\frac{n h c}{\lambda t} \Rightarrow P \propto n / t \)
\(\frac{P_1}{P_2} =\frac{1.38 \times 10^{15}}{460} \times \frac{520}{1.04 \times 10^{15}}=1.5\)