The range of voltmeter is 10V and its internal resistance is 50Ω.

⇦

⇨

The range of voltmeter is 10V and its internal resistance is 50Ω. To convert it to a voltmeter of range 15V, how much resistance is to be added?

Options

(a) Add 25Ω resistor is parallel
(b) Add 25Ω resistor is series
(c) Add 125Ω resistor in parallel
(d) Add 125Ω resistor in series

Correct Answer:

Add 25Ω resistor is series

Explanation:

The current in case of voltmeter range 10 V and resistance 50 Ω is I = 10 / 50 —–(i)

Let X is the resistance conneced in order to make a voltmeter with range 15 V is I = 15 / X —-(ii)

Equating equation (i) and (ii), we get

15 / X = 10 / 50 ⇒ X = (15 × 50) = 75 Ω

Then, R = 75 – 50 = 25 Ω must be connected in series, because V ∝ R when current is constant.

Related Questions:

1. A 200 W sodium street lamp emits yellow light of wavelength 0.6 µm
2. At what height h above earth, the value of g becomes g/2 (where R=radius of earth)?
3. A radioactive substance emits n beta particles in the first 2 s and 0.5 n beta
4. An object is placed 30 cm away from a convex lens of focal length 10 cm and a sharp
5. The friction of the air causes a vertical retardation equal to 10%

Topics: Current Electricity (136)
Subject: Physics (2479)

---

Important MCQs Based on Medical Entrance Examinations To Improve Your NEET Score

18000+ students are using NEETLab to improve their score. What about you?

Solve Previous Year MCQs, Mock Tests, Topicwise Practice Tests, Identify Weak Topics, Formula Flash cards and much more is available in NEETLab Android App to improve your NEET score.

---

Share this page with your friends