In a mass spectrometer used for measuring the masses of ions, the ions

⇦

⇨

In a mass spectrometer used for measuring the masses of ions, the ions are initially accelerated by an electric potential V and then made to describe semicircular path of radius R using a magnetic field B. If V and B are kept constant, the ratio ( charge on the ion / mass of the ion) will be proportional to

Options

(a) 1/R²
(b) R²
(c) R
(d) 1/R

Correct Answer:

1/R²

Explanation:

In mass spectrometer, when ions are accelerated through potential V
1/2 mv² = qV …..(i)
As the magnetic field curves the path of the ions in a semiciruclar orbit
Bqv = mv² / R v = BqR / m ….(ii)
Substituting (ii) and (i)
1/2 m[ BqR / m]² = qv or q/m = 2V / B²R²
Since V and B are constants, q/m ∞ 1/R²

Related Questions:

1. An aeroplane flies 400m due to North and then 300m due to south and then flies
2. A bus is moving with a speed of 10 ms⁻¹ on a straight road
3. Radius of a soap bubble is increased from R to 2R. Work done in this process
4. The distance of a geo-stationary satellite from the centre of the earth is nearest to
5. At place on earth, the vertical component of earth’s magnetic field is √3 times

Topics: Magnetic Effects of Current and Magnetism (167)
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