Dual Nature of Radiation and Matter Test

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Dual Nature of Radiation and Matter Test - 18

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Weekly Quiz Competition

Question 1
1 / -0

The minimum amount of energy required to emit an electron from a metal surface is called

A
Force function

B
Power function

C
Work function

D
None of the above

Solution

The minimum quantity of energy which is required to remove an electron to infinity from the surface of a given solid , usually a metal,is called its work function.
Question 2
1 / -0

The minimum amount of energy required to emit electrons from a metal surface is called

A
work function

B
bound energy

C
nuclear energy

D
all of the above

Solution

The minimum energy that is required to move an electron to infinity from the surface of a solid material, usually a metal is known work function.
Question 3
1 / -0

A plot of the kinetic energy $$(1/2 mv^2)$$ of ejected electrons as a function of the frequency (v) of incident radiation for four alkali metals $$(M_1, M_2, M_3, M_4)$$ is shown below:
The alkali metals $$M_1, M_2, M_3$$ and $$M_4$$ are respectively

A
Li, Na, K and Rb

B
Rb, K, Na and Li

C
Na, K, Li and Rb

D
Rb, Li, Na and K

Solution

$$\frac {1}{2}mv^2=hv-W$$
High is the thershold frequency of metal greater will be the work function.
So,
$$M_1\rightarrow Rb; M_2\rightarrow K; M_3\rightarrow Na; M_4\rightarrow Li$$
Question 4
1 / -0

Stopping potential is the negative voltage on the collector plate at which the photoelectric current just becomes __________.

A
$$>V$$

B
$$< V$$

C
$$Zero$$

D
None of the above

Solution

The negative potential of the collector plate at which the photoelectric current becomes zero is called stopping potential or cut - off potential. Stopping potential is that value of retarding potential difference between two plates which is just sufficient to halt the most energetic photo electron emitter, it is denoted by $$V_{0}$$ .
Question 5
1 / -0

The subatomic particle that is emitted from a metal surface, when it is heated is a/an _________ .

A
proton

B
electron

C
positron

D
neutron

Solution

B
These are free electrons in the metal. When heat energy is applied these free electrons absorb energy and emitted from the surface of the metal. The process by which free electrons are emitted from the surface of a metal when external heat energy is applied is called thermonic emission. Thermonic emission occurs in metals that are heated to a very high temperature.
Question 6
1 / -0

A graph of vacuum diode current $${I}_{p}$$, is plotted against the anode voltage $${V}_{p}$$ for two different temperatures $${T}_{1}$$ and $${T}_{2}$$ of the cathode, as shown in the figure below. Study the graph and answer the following questions.
For the same anode voltage, (called plate voltage), the current more when the cathode temperature changes from $${T}_{1}$$ to $${T}_{2}$$ higher temperature.

A
More number of electron undergo collision

B
More electrons are emitted

C
Resistance increases

D
Voltage increases
Question 7
1 / -0

State the approximate value of work function of an alkali metal in eV.

A
0.2 to 0.3 eV

B
2 to 3 eV

C
20 to 30 eV

D
200 to 300 eV

Solution

Values of Li,K,Cs,Na all lies approximately between 2eV to 3eV.
Question 8
1 / -0

For the same kinetic energy, the momentum shall be minimum for

A
Electron

B
Proton

C
Neutron

D
Alpha particle

Solution

$$\because$$ Kinetic energy, $$K=\displaystyle\frac{P^2}{2m}$$
Here $$K$$ is constant, so $$P\;\propto\;\sqrt{m}$$
Hence electron has minimum momentum
Question 9
1 / -0

Fill in the blanks :
An electron emitter must have ...................... work function and .................... melting point.

A
high, high

B
low, low

C
high, low

D
low, high

Solution

The work function should be low, so that electron is emitted even when it is heated at low temperatures.
The melting point should be high, so that it does not melt when heated.
Question 10
1 / -0

$$1 eV $$=?

A
$$1.9 \times 10^{-16} J$$

B
$$26.6 \times 10^{-31} J$$

C
$$1.6 \times 10^{-19} J$$

D
$$2.2 J$$

Solution

$$1 eV = 1.6 \times 10^{-19}J$$
One electron volt is defined as the energy gained by an electron when it is accelerated through a potential difference of 1 volt.

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Dual Nature of Radiation and Matter Test - 18

Result

Dual Nature of Radiation and Matter Test - 18

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SHARING IS CARING

Question 1

Force function

Power function

Work function

None of the above

Solution

Question 2

work function

bound energy

nuclear energy

all of the above

Solution

Question 3

Li, Na, K and Rb

Rb, K, Na and Li

Na, K, Li and Rb

Rb, Li, Na and K

Solution

Question 4

$$>V$$

$$< V$$

$$Zero$$

None of the above

Solution

Question 5

proton

electron

positron

neutron

Solution

Question 6

More number of electron undergo collision

More electrons are emitted

Resistance increases

Voltage increases

Question 7

0.2 to 0.3 eV

2 to 3 eV

20 to 30 eV

200 to 300 eV

Solution

Question 8

Electron

Proton

Neutron

Alpha particle

Solution

Question 9

high, high

low, low

high, low

low, high

Solution

Question 10

$$1.9 \times 10^{-16} J$$

$$26.6 \times 10^{-31} J$$

$$1.6 \times 10^{-19} J$$

$$2.2 J$$

Solution

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