Question

1. A 1.5- volt battery is connected across an LED bulb, but the bulb does not “light up.” What are two possible reasons why it’s not lighting? (Both the battery and LED are in working order,)

2. ) In what way are an LED and a solar cell alike? In what ways are they different

Please explain everything in detail, I have a lot of difficulty with science. Thank you!

Answer 1

1) The two possibilities of not lighting LED are:

(a) May be LED is connected in reverse biasing with the battery.

(b) May be operating voltage is greater than 1.5 Volts.

2) Similarities between LED and Solar Cell:

(a) Both solar cell and LED are pn juction devices.

(b) Forbidden energy gap of the materials used for formation of LED and solar cells lie nearly in the same range.

(C) Bothe the devices converts energy from one form to another.

Differences between LED and Solar Cell:

(a) LED consumes electrical power while solar cell delivers electrical power.

(b) LED converts electrical energy into light energy while solar cell converts light energy into electrical energy.

(c) In LED light emitted have wavelength corrssponding to the forbidden energy gap of its material while in solar cell it should be fabricated by the material whose forbidden energy gap is reliable with the wavelength of light.

(d) For operating LED it should be connected in forward bias with the battery while solar cell does not require any external biasing to function.