Home
Class 12
PHYSICS
An LED is constructed from a pn junction...

An LED is constructed from a pn junction based on a certain semi-conducting material whose energy gap is 1.9 eV. Then the wavelength of the emitted light is

A

`1.6xx10^(8)m`

B

`9.1xx10^(-5)m`

C

`2.9 xx1^(-9)m`

D

`6.5xx10^(-7)m`

Text Solution

Verified by Experts

The correct Answer is:
D
Given `E=1.9 eV`
`E=(hc)/lamda` ,
`implies lamda =(hc)/E=(6.62xx10^(-34)xx3xx10^6)/(1.9xx1.6xx10^(-19))`
`lamda = 6.5 xx10^(-7)m`.
Promotional Banner

Topper's Solved these Questions

  • SOLIDS & SEMICONDUCTOR DEVICES

    MODERN PUBLICATION|Exercise Revision Test|28 Videos

  • SOLIDS & SEMICONDUCTOR DEVICES

    MODERN PUBLICATION|Exercise Multiple Choice Questions - LEVEL -III (Questions From AIEEE/JEE Examination)|9 Videos

  • ROTATIONAL MOTION

    MODERN PUBLICATION|Exercise RCQ|8 Videos

  • TRANSFERENCE OF HEAT

    MODERN PUBLICATION|Exercise Recent Competitive Questions|4 Videos

Similar Questions

Explore conceptually related problems

The ground state energy of hydrogen atom is - 13.6 eV. If an electron makes a transition from an energy level - 0.85 eV to -3.4 eV, calculate the wavelength of the spectral line emitted. To which series of hydrogen spectrum does this wavelength belong?

Gallium Arsenide used in LED has energy gap 1.2 eV. Light emitted is in

Energy of the electron in hydrogen atom is 1.5 timesas much ass the minimum energy required for its escape (13.6eV) from the atom. Wavelength of the emitted electron is

Energy required to shift an electron from valence band to conduction band of a semiconductor is 1.2 eV, the width of forbidden band is

when a certain energy is applied to an hydrogen atom, an electron jumps from n =1 to n = 3 state. Find (i) the energy absorbed by the electron. (ii) wavelength of radiation emitted when the electron jump back to its initial state. ( Energy of electron in first orbit = - 13.6 eV , Planck's constant = 6.6225 xx10^(-34) Js, Charge on electron = 1.6 xx10^(-19) C, speed of light in vacuum = 3xx10^(8)ms^(-1)

The figure shows the energy level of certain atom. When the electron deexcites from 3E to E, an electromagnetic wave of wavelength lamda is emitted. What is the wavelength of the electromagnetic wave emitted when the electron de excites from (5E)/(3) to E?

A telescope of aperture 0.15 m is used to view two heavenly separated by a certain linear distance. If the distance of these two is 1 million light years from the earth and the wavelength of light emitted is 449 nm, the calculate the linear separation between them.

Light of wavelength 4700Å is incident on a metal plate whose work function is 2 eV. Then maximum kinetic energy of the emitted photoelectron would be

MODERN PUBLICATION-SOLIDS & SEMICONDUCTOR DEVICES-Recent Competitive Questions
  1. Copper and Germanium are cooled from room temperature to 100 K . Then ...

    Text Solution

    |

  2. For a transistor , beta = 100 . The value of alpha is

    Text Solution

    |

  3. The following truth table with A and B as inputs is for ………., gate .

    Text Solution

    |

  4. In which of the following statements, the obtained impure semiconducto...

    Text Solution

    |

  5. The width of the depletion region in a P-N junction diode is

    Text Solution

    |

  6. When the transistor is used as an amplifier

    Text Solution

    |

  7. Which one of the following is not correct?

    Text Solution

    |

  8. The output of an OR gate is connected to both the inputs of a NAND gat...

    Text Solution

    |

  9. in n type semiconductor, electrons are majority charge carriers but do...

    Text Solution

    |

  10. For the gives digital circuit write the truth table and identify the l...

    Text Solution

    |

  11. If alpha-current gain of a transistor is 0.98 . What is the value of ...

    Text Solution

    |

  12. The circuit has two oppositely connected ideal diodes in parallel . Wh...

    Text Solution

    |

  13. An LED is constructed from a pn junction based on a certain semi-condu...

    Text Solution

    |

  14. The given table is for {:("Input","Output"),(A" "B,Y),("0 0",...

    Text Solution

    |

  15. The input characteristics of a transistor in CE mode is the graph obta...

    Text Solution

    |

  16. In a transistor connected in a common emitter mode, Ro-4kW, Ri=1W,Ic=1...

    Text Solution

    |

  17. In a semi conductor diode, the reverse biased current is due to drift ...

    Text Solution

    |

  18. In case of p-n junction diode at high value of reverse bias, the curre...

    Text Solution

    |

  19. The given table is for {:("Input","Output"),(A" "B,Y),("0 0",...

    Text Solution

    |

  20. In a transistor connected in a common emitter mode, Ro-4kOmega, Ri=1Om...

    Text Solution

    |