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If light of wavelength of maximum intensity emitted from surface at temperature `T_(1)` Is used to cause photoelectric emission from a metallic surface, the maximum kinetic energy of the amitted electron is 6 ev, which is 3 time the work function of the metallic surface. If light of wavelength of maximum intensity emitted from a surface at temperature `T_(2) (T_(2)=2T_(1))` is used, the maximum kinetic energy of the photoelectrons emitted is

A

2 eV

B

4 eV

C

14 eV

D

18 eV

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The correct Answer is:
To solve the problem step by step, we will analyze the information given and apply the relevant physics concepts. ### Step 1: Understand the relationship between kinetic energy and work function We know that the maximum kinetic energy (K.E.) of the emitted electrons can be expressed as: \[ K.E. = E - \phi \] where \( E \) is the energy of the incident photons and \( \phi \) is the work function of the metallic surface. ### Step 2: Determine the work function From the problem, we are given that the maximum kinetic energy of the emitted electrons when light of wavelength corresponding to temperature \( T_1 \) is used is 6 eV, and this is three times the work function: \[ K.E. = 3\phi \] Thus, we can express the work function as: \[ \phi = \frac{K.E.}{3} = \frac{6 \text{ eV}}{3} = 2 \text{ eV} \] ### Step 3: Calculate the energy of the incident photons at temperature \( T_1 \) The energy of the photons can be calculated using the equation: \[ E = K.E. + \phi \] Substituting the known values: \[ E = 6 \text{ eV} + 2 \text{ eV} = 8 \text{ eV} \] ### Step 4: Relate the energy of the photons to wavelength The energy of the photons can also be expressed in terms of wavelength: \[ E = \frac{hc}{\lambda} \] Setting this equal to the energy calculated: \[ \frac{hc}{\lambda_1} = 8 \text{ eV} \] ### Step 5: Analyze the situation at temperature \( T_2 \) We are given that \( T_2 = 2T_1 \). The wavelength of the maximum intensity emitted from a black body is given by Wien's displacement law: \[ \lambda_{max} \propto \frac{1}{T} \] Thus, if \( T_2 = 2T_1 \), then: \[ \lambda_2 = \frac{\lambda_1}{2} \] ### Step 6: Calculate the energy of the photons at temperature \( T_2 \) Using the relationship for energy again, we find: \[ E_2 = \frac{hc}{\lambda_2} = \frac{hc}{\frac{\lambda_1}{2}} = 2 \cdot \frac{hc}{\lambda_1} = 2E_1 \] Since \( E_1 = 8 \text{ eV} \): \[ E_2 = 2 \cdot 8 \text{ eV} = 16 \text{ eV} \] ### Step 7: Calculate the maximum kinetic energy at temperature \( T_2 \) Now we can find the new maximum kinetic energy using the same formula: \[ K.E. = E_2 - \phi \] Substituting the values: \[ K.E. = 16 \text{ eV} - 2 \text{ eV} = 14 \text{ eV} \] ### Final Answer The maximum kinetic energy of the photoelectrons emitted when light of wavelength corresponding to temperature \( T_2 \) is used is: \[ \boxed{14 \text{ eV}} \]

To solve the problem step by step, we will analyze the information given and apply the relevant physics concepts. ### Step 1: Understand the relationship between kinetic energy and work function We know that the maximum kinetic energy (K.E.) of the emitted electrons can be expressed as: \[ K.E. = E - \phi \] where \( E \) is the energy of the incident photons and \( \phi \) is the work function of the metallic surface. ### Step 2: Determine the work function ...
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