Resistors and are placed in parallel as shown. If they have values of and respectively, their combined equivalent resistance is:
1
0.032
2
0.32
3
3.022
4
3.312
Official Solution
Correct Option: (4)
The equivalent resistance for parallel resistors is given by:
Substituting the values:
Therefore, .
02
PYQ 2017
medium
physicsID: ipu-cet-
Consider the analogy between an oscillating spring-body system and an oscillating L-C-R circuit. Then, the correspondence between the two systems that is NOT correct is:
1
charge corresponds to displacement of the body
2
inductance corresponds to mass of the body
3
capacitance corresponds to spring constant
4
magnetic energy corresponds to kinetic energy of the body
Official Solution
Correct Option: (3)
In an oscillating spring-body system and an oscillating L-C-R circuit, there are several analogies between the two systems. These analogies are based on the nature of the oscillations in both systems: - The charge in the L-C-R circuit corresponds to the displacement of the body in the spring system. This is because both quantities describe the position of the system at any given time.
- The inductance in the L-C-R circuit corresponds to the mass of the body in the spring system, as both terms are related to inertia in the respective systems.
- The capacitance in the L-C-R circuit corresponds to the spring constant in the spring-body system. However, this analogy is incorrect. In fact, the spring constant is related to the restoring force in the spring-body system, while the capacitance in the L-C-R circuit relates to the storage of energy in the electric field of the capacitor. The correct analogy is that the spring constant corresponds to the inverse of the capacitance. Therefore, the correct answer is (c).
