Physics - Online Test
Q1. For a series LCR circuit the input impedance at resonance
Answer : Option C
Explaination / Solution:
Impedance in series LCR circuit
at resonance
Q2. The electric dipole potential falls off, at large distance r
Answer : Option D
Explaination / Solution:
The potential due to a dipole at a point (r ,θ)from its center is therefore,
Q3. in laminar flow
Answer : Option C
Explaination / Solution:
laminar flow (or streamline flow) occurs when a fluid flows in parallel layers, with no disruption between the layers. At low velocities, the fluid tends to flow without lateral mixing, and adjacent layers slide past one another like playing cards.
Q4. The number of degrees of freedom a diatomic molecule is
Answer : Option B
Explaination / Solution:
Degrees of freedom of a system refers to the possible independent motions a system can have.
the total degrees of freedom describing the motion of a diatomic molecule is 5.
3 for translation and 2 for rotation
Q5. Thin lens approximation for a lens is
Answer : Option B
Explaination / Solution:
No Explaination.
Q6. The difference in mass of a nucleus and its constituents is called
Answer : Option C
Explaination / Solution:
The mass defect of a nucleus represents the mass of the energy of binding of the nucleus, and is the difference between the mass of a nucleus and the sum of the masses of the nucleons of which it is composed.
Q7. expansion of water is called anomalous because
Answer : Option B
Explaination / Solution:
Liquids expand on heating and contract on cooling at moderate temperatures. But water exhibits an exceptional behaviour. When it is heated from 0 ºC, it actually contracts rather than expanding, up to 4 ºC. The volume of water is minimum at 4 ºC. Beyond 4 ºC, water starts expanding.This behaviour of water between 0 ºC and 4 ºC is called anomalous expansion of water..
Q8. The magnetic field at the center of a solenoid coil having n turns and carrying a current I in air is
Answer : Option B
Explaination / Solution:
The magnetic field at the centre of a solenoid with air core is .where,is the permeability of free space, n the number of turns per unit length and I is the current flowing through the solenoid.
Q9. The relative error is given by
Answer : Option B
Explaination / Solution:
Relative Error or fractional error : It is defined as the ration of mean absolute error to the mean value of the measured quantity.
Q10. Find the pd between A and B from the figure
Answer : Option A
Explaination / Solution:
The resistance in the arm CAD RCAD = 4 + 6 = 10Omega .
The resistance in the arm CBD RCBD = 6 + 4 = 10Omega
Since the resistances in both the arms are equal, the current splits equally in the arms.ICAD = ICBD = 4/2 = 2A.
The potential difference across A and C.VAC = VA - VC = ICAD * RAC = 2 * 4 = 8V
potential difference across B and C VBC = VB - VC = ICBD * RBC = 2 * 6 = 12V.The potential difference across A and B VBA = VB - VA = VBC - VAC = 12 - 8 = 4V.
Point B is at a higher potential when compared to A.
