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At any junction, the sum of the currents entering the junction is equal to the sum of _______
  • a)
    potential around any closed loop
  • b)
    voltages across the junction
  • c)
    all the currents in the circuit
  • d)
    currents leaving the junction
Correct answer is option 'D'. Can you explain this answer?

Om Kumar answered
The correct answer is option 'D': currents leaving the junction.

Explanation:
At any junction in an electrical circuit, the sum of the currents entering the junction is equal to the sum of the currents leaving the junction. This is based on the principle of conservation of charge.

When current flows through a junction, it must split into multiple paths. The total amount of charge entering the junction must be equal to the total amount of charge leaving the junction. This is because charge cannot be created or destroyed, it can only flow through the circuit.

To better understand this concept, consider a simple circuit with three branches connected to a junction. Let's label the currents entering the junction as I1, I2, and I3, and the currents leaving the junction as I4, I5, and I6.

The principle of conservation of charge states that the total amount of charge entering the junction must be equal to the total amount of charge leaving the junction. Mathematically, this can be expressed as:

I1 + I2 + I3 = I4 + I5 + I6

This equation shows that the sum of the currents entering the junction (I1 + I2 + I3) is equal to the sum of the currents leaving the junction (I4 + I5 + I6).

This principle is a consequence of Kirchhoff's current law (KCL), which states that the algebraic sum of currents at any junction in an electrical circuit is zero. This means that the sum of currents entering the junction is equal to the sum of currents leaving the junction.

In summary, at any junction in an electrical circuit, the sum of the currents entering the junction is equal to the sum of the currents leaving the junction. This principle is based on the conservation of charge and is a consequence of Kirchhoff's current law.

The Wheatstone bridge Principle is deduced using
  • a)
    Gauss’s Law
  • b)
    Kirchhoff’s Laws
  • c)
    Coulomb’s Law
  • d)
    Newton’s Laws
Correct answer is option 'B'. Can you explain this answer?

Anjana Sharma answered
PRINCIPLE: Wheatstone bridge principle states that when the bridge is balanced, the product of the resistance of the opposite arms are equal. The files that I had attached in which I had derived Wheatstone bridge equation using Kirchhoff law is useful to you.

Can you explain the answer of this question below:
The ______ of changes in potential around any closed loop involving resistors and cells in a loop is zero.
  • A:
    product
  • B:
    algebraic sum
  • C:
    difference
  • D:
    sum of absolute values
The answer is b.

Lavanya Menon answered
In accordance with Kirchhoff’s second law i.e. Kirchhoff’s voltage law (KVL), the algebraic sum of all the potential differences in a closed electric circuit or closed loop that contains one or more cells and resistors is always equal to zero.
This law is popularly called the law of conservation of voltage.
 

Given N resistors each of resistance R are first combined to get minimum possible resistance and then combined to get maximum possible resistance. The ratio of the minimum to maximum resistance is​
  • a)
    N
  • b)
    N2
  • c)
    1/N2
  • d)
    1/N
Correct answer is option 'C'. Can you explain this answer?

Nishtha Bose answered
They are connected in series to get maximum in this case resistance would be nr
and to get minimun resistance they are connected in parallel :. resistance in this case is n/r
:. ratio between minimum and maximum resistance is n/r/nr = 1/r^2

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