3-1 week review

full form of LED

• light emitting diode

• light limiting diode

• light storing diode

• light electrification diode

led works only in ______ bias

• Forward

• Reverse

The colour of emitted light from LED depends on

• physical dimensions of LED

• Number of available carriers

• Type of semiconductor material used

• Number of recombinations taking place

The advantage of LED is

• Low operating voltage

• Long Life

• Small in Size

• All the above

An LED made up of ______________________

• Germanium

• Silicon

• Silicon Carbide

• None

In LED electron energy form of ______________________

• Hole

• Electron

• Neutron

• Photon

An LED is called __________

• Direct gap type semiconductor

• Indirect gap type semiconductor

• Forbidden gape type

• None

An LED is a ____________________________

• Light emission device

• Light observing device

• Both light emission and observing device

• Light emission or observing device

An LED is _______________________ device

• Passive

• Bi-directional

• Uni-directional

• Different directional

How long can a LED light last

• 50000 hours

• 2000 days

• 10 years

• 2000000000000000 seconds