Physics - Online Test
Q1. Transformer uses the follwing principle of
Answer : Option C
Explaination / Solution:
A transformer consists of two electrically isolated coils. It works on the principle of mutual induction of two coils or Faraday Law’s Of Electromagnetic induction. When current in the primary coil is changed the flux linked to the secondary coil also changes.hence an EMF is induced in the secondary coil due to Faraday law’s of electromagnetic induction.
Q2. Electrostatic shielding is based
Answer : Option B
Explaination / Solution:
Electric field inside a cavity is always zero. The potential inside a cavity of a conductor is constant. The potential difference between any two points inside a charged conductor is zero. This phenomenon is called electrostatic shielding.
Q3. The moment of inertia of a planar body (lamina) about an axis perpendicular to its plane is.
Answer : Option C
Explaination / Solution:
According to perpendicular axis theorem "For a planar object, the moment of inertia about an axis perpendicular to the plane is the sum of the moments of inertia of two perpendicular axes through the same point in the plane of the object".
Q4. The lift on an aircraft wing arises because of
Answer : Option C
Explaination / Solution:
This is the application of Bernoulli's Theorem.
If air speeds up the pressure is lowered.Thus,a wing generates lift because the air goes faster over the top creating a region of low pressure,and thus lift.
Q5.
For a rope of yield strength loaded in tension with weight Mg the minimum area A of the rope should be
Answer : Option C
Explaination / Solution:
We know that Yield strength times the Area give the weight of the body.
As Yield strength = weight of body/area
For safety purposes
Yield strength weight of body/area
Mg/A
A Mg/
Q6. At the minimum deviation , the refracted ray inside the prism
Answer : Option B
Explaination / Solution:
No Explaination.
Q7. Energies associated with nuclear processes are
Answer : Option A
Explaination / Solution:
No Explaination.
Q8. If m is the mass of a substance, ΔQ the energy required to raise the temperature by ΔT the specific heat is given by
Answer : Option D
Explaination / Solution:
The specific heat is the amount of heat per unit mass required to raise the temperature by one degree Celsius.
Q9. magnetic moment of a single-turn current loop of aluminium wire of area A,carrying a current I in a wire of diameter d is
Answer : Option B
Explaination / Solution:
The torque experienced by a current carrying coil of N turns placed in a magnetic field.For N =1, Comparing with torque experienced by a electric dipole
Q10. The relative error in a physical quantity raised to the power k is.
Answer : Option A
Explaination / Solution:
The relative error in a physical quantity raised to a power k is the k times the relative error in the individual quantity.
for e.g.
maximun relative error,
