CBSE 12TH PHYSICS - Online Test
Q1. For a parallel ideal LC circuit at resonance the input impedance across L or C is______
Answer : Option D
Explaination / Solution:
in parallel LC circuit, Impedance
at resonance
hence impedance will be infinite.
Q2. At the surface of a charged conductor, electrostatic field must be
Answer : Option A
Explaination / Solution:
Under static conditions, no current exists on the surface of a conductor. If the electric field at its surface is tangential or parallel to the surface, the tangential electric field would cause the charges to move on the surface of the conductor causing currents to flow on its surface. Therefore electrostatic field is always normal to the surface of a charged conductor at every point.
Q3. If several thin lenses of focal length … are in contact, the effective focal length is
Answer : Option D
Explaination / Solution:
No Explaination.
Q4. In the mass number range A = 30 to 170, the binding energy per nucleon is
Answer : Option D
Explaination / Solution:
Binding energy per nucleon vs atomic mass curve
Q5. A rectangular current-carrying coil having n turns,area A and a current I flowing, in a uniform magnetic field B experiences a maximum ,torque equal to
Answer : Option A
Explaination / Solution:
The torque experienced by a current carrying conductor placed in a magnetic field is given by .This has a maximum value when;
Q6. In a meter bridge experiment a balance point is obtained at a distance of 60 cm from the left end when unknown resistance R is in a left gap and 8 ohms resistor is connected in the right gap. When the position of R and 8 ohm resistor is interchanged the balance point will be at distance of
Answer : Option A
Explaination / Solution:
The balance point when 8Ω is in the left gap will be 40 cm.
Q7. Referring to the Young’s double slit experiment, Path Difference corresponding to a Phase difference of π/3 is
Answer : Option C
Explaination / Solution:
No Explaination.
Q8. Diamagnetic substances are
Answer : Option D
Explaination / Solution:
No Explaination.
Q9. In a p-n junction, as the diffusion process continues the width of the depletion zone
Answer : Option D
Explaination / Solution:
No Explaination.
Q10. Infrared waves are produced by
Answer : Option D
Explaination / Solution:
No Explaination.
