12th Class FSC Part 2 Physics Online Test

With the speed of motor, magnitude of back emf

• Remain same A
• Increase B
• Decrease C
• First increases then decreases D

• 
  A
• 
  B
• 
  C
• 
  D

A radio active substance has a half life of four months. 3 -fourth of the substance will decay in:

• 6 months A
• 8 months B
• 12 months C
• 16 months D

___ is correct relation.

• IT = 10^-4 G A
• IT = 10⁴ G B
• IT = 10² G C
• IT = 10 ^-2 G D

Resistance tolerance of silver band is.

• 10% A
• 6% B
• 7% C
• 5% D

In an N-type silicon, which of the following statement is true?

• Electrons are majority carriers & trivalent atoms are the dopants A
• Electrons are majority carriers & pentavalent atoms are the dopants B
• Holes are minority carriers & pentavalent atoms are the dopants. C
• Holes are minority carriers & trivavalent atoms are the dopants. D

the force between two charge is 28 N. If paraffin wax of relative permittivity 2.8 is introduced between the charges as medium, then the force reduces to.

• 25 N A
• 20 N B
• 10 N C
• 15 N D

The peak value of alternating current is 5√2 A. The mean square value of current will be:

• 5A A
• 2.5A B
• 5√2A C
• 5² D

In A.C circuit of inductor which one is true

• Voltage leads current by phase angle π/2 A
• Voltage lags current by π/2 B
• Current leads voltage by π/2 C
• Both remain in phase D

The gain of transistor amplifier depends upon

• Resistance connected with collector A
• Resistance connected with base voltage B
• Input voltage C
• Output voltage D

The input resistance of an op amplifier is.

• Low A
• High B
• Zero C
• Equal to output resistance D

A wire uniform cross-section. A length L and resistance R is cut into two equal parts. The resistivity of each part will be:

• Doubled A
• Halved B
• Remain the same C
• One fourth D

When a very high energy modeules such as y radiation interact with matter, the phenomenon arising will be.

• Photoelectric effect A
• Compton effect B
• Pair production C
• Annihilation of matter D

In three phase voltage across any two lines is about.

• 220 V A
• 230 V B
• 400 V C
• 430 V D

Conversation of only one half of A.C. into D.C. is called.

• Half wave amplification A
• Wave amplification B
• Half wave electrification C
• Half wave rectification D

Which one is pentavalent impurity

• Boron A
• Gallium B
• Antimony C
• Indium D

Which is not characteristic of Laser.

• Monochromatic A
• Coherent B
• Intense C
• Multi direction D