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

Max planck received noble prize in:

• 1927 A
• 1932 B
• 1918 C
• 1914 D

The powers of two electric bulbs are 100w and 200w. Which are connected to power supply of 220 V. The ratio of resistance of their filament will be:

• 1:2 A
• 2:1 B
• 1:3 C
• 4:3 D

Glass and high steel carbon are example of.

• Ductile substances A
• Brittle substances B
• Soft substances C
• Hard substances D

The unit of induced emf is

• Ampere A
• Volt B
• Joule/coulomb C
• Both (b) and (c) D

Photo electrons are emitted y using visible light when the metal is.

• sodium A
• Copper B
• Nicked C
• Cobalt D

In A.C circuit through a capacitor which one is:

• Current leads voltage by 90^∘ A
• Current lags behind voltage by 90^∘ B
• Both will be in phase C
• None of above  D

The only difference between the construction of D.C and A.C is.

• Carbon burshes A
• Coil B
• Commutator C
• Magnetic field D

The phase difference between the current and voltage at resonce is:

• 0 A
• π B
• -π C
• π/2 D

• 
  A
• 
  B
• 
  C
• 
  D

The output of two input is zero only when its.

• Both inputs are zero A
• Either input is zero B
• Both inputs are one C
• Either input is one D

Output resistance of an op amp is

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

If I_o is the peak value of current, then its root mean square value is given by

• 
  A
• 2 I_o B
• I_o C
• 0.7 I_o D

If magnetic field is doubled then magnetic energy density becomes.

• Four times A
• Two times B
• Three times C
• Six times D

Half life of radon gas is

• 3.8 minutes A
• 3.8 days B
• 3.8 months C
• 3.8 years D

Electro magnetic waves emitted from radio antenna are.

• Stationary A
• Longitudinal B
• Transvers C
• Both a and b D

The wavelength associated with the protons moving at speed of 40 m/s is.

• 7.20 nm A
• 9.02 B
• 15.7 nm C
• 17.3 nm D