The effective resistance of a parallel connection that consists of four wires of equal length, equal area of cross-section and same material is $0.25\, \Omega$. What will be the effective resistance if they are connected in series?
- $0.25\, \Omega$
- $0.5\, \Omega$
- $1\, \Omega$
- $4\, \Omega$
The Correct Option is D
Solution and Explanation
$R _{ eq }= R / 4=0.25$
$\Rightarrow R =1 \Omega$
So, after they are connected in series
$R _{ eq }=4 R =4 \Omega$
Top Questions on Resistance
- Find the effective resistance of the network of resistors between points A and F as shown in the figure.
- A current of 2 A flows through a conductor with a resistance of 5 \(\Omega\). Calculate the potential difference across the conductor.
- MHT CET - 2025
- Physics
- Resistance
- A coil of resistance 10 \( \Omega \) is connected to a battery of 12 V. If the current flowing through the coil is 2 A, what is the power dissipated in the coil?
- BITSAT - 2025
- Physics
- Resistance
- A wire of resistance \( X \, \Omega \) is gradually stretched till its length becomes twice its original length. If its new resistance becomes 40 \( \Omega \), find the value of \( X \).
- A wire of resistance \( R \), connected to an ideal battery, consumes a power \( P \). If the wire is gradually stretched to double its initial length, and connected across the same battery, the power consumed will be:
Questions Asked in NEET exam
Given below are two statements: One is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A): A typical unfertilized, angiosperm embryo sac at maturity is 8-nucleate and 7-celled.
Reason (R): The egg apparatus has 2 polar nuclei.In the light of the above statements, choose the correct answer from the options given below:
- NEET (UG) - 2025
- Angiosperms
- A ball of mass 0.5 kg is dropped from a height of 10 m. The ball hits the ground and rises to a height of 1.5 m. The impulse imparted to the ball during its collision with the ground is : (Take \(g = 9.8 \, \text{m/s}^2\))
- NEET (UG) - 2025
- Collision and Impulse
- Consider the diameter of a spherical object being measured with the help of a Vernier Callipers. Suppose its 10 Vernier Scale Divisions (V.S.D.) are equal to its 9 Main Scale Divisions (M.S.D.). The least count in the M.S. is 0.1 cm and the zero of V.S. is at -0.1 cm when the jaws of Vernier callipers are closed. If the main scale reading for the diameter is \(M = 5\) cm and the number of coinciding vernier division is 8, the measured diameter after zero error correction, is:
- NEET (UG) - 2025
- Measurement of length
- A container has two chambers of volumes \(V_1 = 2\) litres and \(V_2 = 3\) litres separated by a partition made of a thermal insulator. The chambers contain \(n_1 = 2\) moles and \(n_2 = 3\) moles of ideal gas at pressures \(p_1 = 1\) atm and \(p_2 = 2\) atm, respectively. When the partition is removed, the mixture attains an equilibrium pressure of :
- NEET (UG) - 2025
- Ideal Gases
A sphere of radius R is cut from a larger solid sphere of radius 2R as shown in the figure. The ratio of the moment of inertia of the smaller sphere to that of the rest part of the sphere about the Y-axis is :
- NEET (UG) - 2025
- Moment Of Inertia
Concepts Used:
Resistance
Resistance is the measure of opposition applied by any object to the flow of electric current. A resistor is an electronic constituent that is used in the circuit with the purpose of offering that specific amount of resistance.
R=V/I
In this case,
v = Voltage across its ends
I = Current flowing through it
All materials resist current flow to some degree. They fall into one of two broad categories:
- Conductors: Materials that offer very little resistance where electrons can move easily. Examples: silver, copper, gold and aluminum.
- Insulators: Materials that present high resistance and restrict the flow of electrons. Examples: Rubber, paper, glass, wood and plastic.
Resistance measurements are normally taken to indicate the condition of a component or a circuit.
- The higher the resistance, the lower the current flow. If abnormally high, one possible cause (among many) could be damaged conductors due to burning or corrosion. All conductors give off some degree of heat, so overheating is an issue often associated with resistance.
- The lower the resistance, the higher the current flow. Possible causes: insulators damaged by moisture or overheating.