MCQ
Alnico is used for making permanent magnets because it has:
  • A
    High coercivity and high retentivity.
  • B
    High coercivity and low retentivity.
  • C
    Low coercivity and low retentivity.
  • D
    Low coercivity and high retentivity.

Answer

  1. High coercivity and high retentivity.

Explanation:

Alnico is used for making permanent magnet because it can be easily magnetised in external magnetic field and It will not lose its magnetic property due to its high coercivity and low retentivity.

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Similar questions

A person who is at rest as the charge moves by him will measure.
Consider a mixture of oxygen and hydrogen kept at room temperature. AB compared to a hydrogen molecule an oxygen molecule hits the wall:
  1. With greater average speed.
  2. With smaller average speed.
  3. With greater average kinetic energy.
  4. With smaller average kinetic energy.

Six charges, three positive and three negative of equal magnitude are to be placed at the vertices of a regular hexagon such that the electric field at O is double the electric field when only one positive charge of same magnitude is placed at R. Which of the following arrangements of charges is possible for P, Q, R, S, T and U respectively

(a) +, -, +, -, -, +

(b) +, -, +, -, +, -

(c) +, +, -, +, -, -

(d) -, +, +, -, +, -

X-rays of   have frequency

(a) 3  

(b) 3 

(c)   

(d)  

Two coherent sources separated by distance d are radiating in phase having wavelength l. A detector moves in a big circle around the  two sources in the plane of the two sources. The angular position of n = 4 interference maxima is given as

(a)  

(b)  

(c)  

(d)  

Which of the following parameters are the same for all hydrogen-like atoms and ions in their ground states?

Bohr's atom model assumes

(a) The nucleus is of infinite mass and is at rest

(b) Electrons in a quantized orbit will not radiate energy

(c) Mass of electron remains constant

(d) All the above conditions

When the key K is pressed at time  t = 0, which of the following statements about the current I in the resistor AB of the given circuit is true

(a) I = 2 mA  at all t

(b) I oscillates between 1 mA and 2mA

(c) I = 1 mA at all t

(d) At t = 0 , I = 2 mA and with time it goes to 1 mA

A circular coil of radius 4 cm and of 20 turns carries a current of 3 amperes. It is placed in a magnetic field of intensity of 0.5 . The magnetic dipole moment of the coil is

(a) 0.15  

(b) 0.3

(c) 0.45

(d) 0.6

What is the torque exerted by a bar magnet on itself due to its field?