CBSE 12TH PHYSICS - Online Test
Q1. A current is passed though two coils connected in series. The potential difference across the first coil of resistance 2 ohm is 5 volt. If the potential difference across the second coil is 12.5 volt the resistance of the second coil is
Answer : Option A
Explaination / Solution:
The current in the circuit
V1 =5 V is the p.d across the first coil of resistance R1=2Ω. The same current flows through the second coil of resistance X. . The p.d across the second coil V2 =12.5 V.
Q2. Referring to the Young’s double slit experiment, Phase difference corresponding to a Path Difference of λ /3 is
Answer : Option A
Explaination / Solution:
No Explaination.
Q3. Magnetic material differences are explained by
Answer : Option D
Explaination / Solution:
No Explaination.
Q4. Depletion region (space charge) is formed because
Answer : Option C
Explaination / Solution:
The depletion region, also called depletion layer, depletion zone, junction region, space charge region or space charge layer, is an insulating region within a conductive, doped semiconductor material where the mobile charge carriers have been diffused away, or have been forced away by an electric field. The only elements left in the depletion region are ionized donor or acceptor impurities.
The depletion region is so named because it is formed from a conducting region by removal of all free charge carriers, leaving none to carry a current.
Q5. Food is heated in a microwave oven because
Answer : Option B
Explaination / Solution:
No Explaination.
Q6. Damping in galvanometers is based on
Answer : Option D
Explaination / Solution:
The coil of galvanometer is wound on a light metal frame. When the coil and frame rotate in the field of the permanent magnet, the eddy current set up in the frame oppose the motion so that the coil returns to zero quickly.
Q7. Photons can be
Answer : Option D
Explaination / Solution:
If photon strike with loosely bound electron then photoelectric effect takes place.Collision of photon with completely free electron give rise to Compton effect or Compton scattering.
Q8. FM Radio set used in cars is
Answer : Option D
Explaination / Solution:
Radio means sending energy with waves. In other words, it's a method of transmitting electrical energy from one place to another without using any kind of direct, wired connection. That's why it's often called wireless. The equipment that sends out a radio wave is known as a transmitter; the radio wave sent by a transmitter whizzes through the air—maybe from one side of the world to the other—and completes its journey when it reaches a second piece of equipment called a receiver((here a radio).
Q9. Electric field lines can be said to be
Answer : Option A
Explaination / Solution:
Electric Field Lines can be defined as a curve which shows direction of electric field, when we draw tangent at its point. The concept of electric field was proposed by Michael Faraday, in the 19th century. He always thought that electric field lines can be used to describe and interpret the invisible electric field. Instead of using complex vector diagram every time, This pictorial representation or form is called electric field lines.
Electric field lines can be used to describe electric field around a system of charges in a better way.
Q10. Which of these statements about Bohr model hypothesis is correct?
Answer : Option C
Explaination / Solution:
No Explaination.
