A student joined three resistances (two of $30\ \Omega$ in series, connected in parallel with a $20\ \Omega$ resistor) to a $7.5\text{ V}$ source. The current recorded by the ammeter (A) is:

Electricity

Electric Circuits

Options

(A)0.25 A

(B)0.5 A

(D)1 A

Official Answer

0.5 A

currentresistanceOhm's law

Marking Scheme

11 mark for correct answer

Hint

Use Ohm's law to find the current in the circuit.

Quick Oral Answer

The current recorded by the ammeter is 0.5 A.

Analysis & Explanation

The correct answer is option B, which is 0.5 A. This is because the total resistance of the circuit is 15 ohms, and the voltage is 7.5 volts. Using Ohm's law, we can calculate the current as I = V/R = 7.5/15 = 0.5 A.

Common Mistakes

1forgetting to calculate the total resistance of the circuit
2not using Ohm's law correctly

Interesting Facts

The concept of resistance was first introduced by Georg Simon Ohm in 1827.

The unit of resistance is named after Ohm.

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Frequently Asked Questions

How many marks does this question carry in CBSE Class 10 Science 2014?

This question carries 1 mark in the CBSE Class 10 Science 2014 examination.

Which chapter does this question come from in Science?

This question is from the chapter "Electricity" in the CBSE Class 10 Science syllabus.

What topic does this question cover in Science?

This question covers the topic "Electric Circuits" from CBSE Class 10 Science.

What type of question is this in the CBSE Class 10 Science 2014 paper?

This is a MCQ question from Section SECTION-B in the CBSE Class 10 Science 2014 paper.