Exams › JEE Main › Physics

Consider a moving coil galvanometer (MCG) : A : The torsional constant in moving coil galvanometer has dimensions [ML^2T^-2] B : Increasing the current sensitivity may not necessarily increase the voltage sensitivity. C : If we increase number of turns (N) to its double (2N), then the voltage sensitivity doubles. D : MCG can be converted into an ammeter by introducing a shunt resistance of large value in parallel with galvanometer. E : Current sensitivity depends inversely on number of turns of coil. Choose the correct answer from the options given below : (1) A, B only (2) A, D only (3) B, D, E only (4) A, B, E only

1. A, B only
2. A, D only
3. B, D, E only
4. A, B, E only

Correct answer: A, B only

Solution

Options A and B are correct because the torsional constant indeed has the dimensions of [ML^2T^-2], and while increasing current sensitivity can enhance the response of the galvanometer, it does not guarantee an increase in voltage sensitivity due to the different factors influencing each type of sensitivity.

Related JEE Main Physics questions

• A tightly wound solenoid has 2000 turns and a cross-sectional area of $1.5 \times 10^{-4}\,\text{m}^2$. It carries a current of 2.0 A and is hung at its center with its axis perpendicular to its length so that it can rotate in a horizontal plane. If it is placed in a uniform magnetic field of strength $5 \times 10^{-2}\,\text{T}$, and the field makes an angle of $30^\circ$ with the solenoid axis, what torque acts on the solenoid?
• A cyclotron with dee radius $R$ is used to speed up protons of mass $m$. An alternating electric field of frequency $\nu$ is applied across the dees. For the cyclotron to operate, the magnetic field $B$ and the kinetic energy $K$ of the emerging proton beam are related by:
• A long, straight conductor of radius $a$ carries a constant current $I$ that is spread uniformly over its cross-sectional area. What is the ratio of the magnetic field at a distance $a/2$ from the axis to the magnetic field at a distance $2a$ from the axis?
• Two tangent galvanometers, A and B, have coil radii of 8 cm and 16 cm respectively, and each has a resistance of 8 $\Omega$. They are joined in parallel. When the applied voltages are 4 V and 6 V respectively, the corresponding deflections in A and B are 30$^\circ$ and 60$^\circ$. If galvanometer A has 2 turns, the number of turns in B is
• A charge of $2\,\mu\text{C}$ revolves with a frequency of $6.25\times 10^{12}\,\text{Hz}$ and creates a magnetic field of $6.28\,\text{T}$ at a point on the circle. What is the radius of the circular path?
• An electron beam travels through a region where uniform electric and magnetic fields act mutually perpendicular to each other, and both are also perpendicular to the direction of motion of the electrons. If the electric field strength is $20\,\text{V m}^{-1}$ and the magnetic field strength is $0.5\,\text{T}$, the speed of the electrons must be

⚔️ Practice JEE Main Physics free + battle 1v1 →