Class test 5: 5.8.2020

LASING action depends on

• Spontaneous emission

• Stimulated emission

• Spontaneous emission followed by stimulated emissions

• Absorption of radiation

Semiconductor materials produces light

• Silicon

• Gallium

• Germanium

• None of the above

Combination of semiconductors that emits blue colour in LED

• Gallium Arsenide

• Gallium Nitrite

• Gallium Arsenide and Phosphide

• Gallium Phosphide

In a LED light output is directly proportional to the ---------------------------------

The switching speed of LEDs is in terms of

• 1nsec

• 1msec

• 1microsec

• 1sec

To turn on the LED in common anode type 7 segment display, LED is to be connected to Supply or to Ground?

If a laser diodes emits light in a direction parallel to the PV junction plane then laser diode is called

• Edge – emitting LASER diode

• Surface Emitting LASER diodes

• Plane Emitting LASER diode

• Diagonal emitting LASER diode

Lasers are used for a variety of applications. Which of the following is an example of areas that lasers are used.

• commercial fields

• scientific fields

• medical applications

• all of the above

To form a LASER diode Gallium Arsenide (GaAs) like materials are to be doped with

• Aluminium

• Silicon

• Selenium

• All the above

Which is the most commonly advertised types of laser surgery today?

• laser dermatology

• laser skin resurfacing

• LASIK

• tattoo removal