The main function of the commutator in a simple d.c. motor is to
enable the armature to rotate freely
increase the flux linking the armature windings
maintain a direct current in the armature
provide uniform magnetic field around the armature
reverse the direction of the current in the armature.
Correct answer is E
No explanation has been provided for this answer.
brass is less dense than clay
clay expands more slowly than brass
clay loses heat faster than brass
the specific heat capacity of brass is higher than that of clay
the specific heat capacity of brass is lower than of clay.
Correct answer is E
No explanation has been provided for this answer.
An object is placed 15cm in front of a concave mirror of focal length 20cm. The image formed is
real, inverted and diminished
real, inverted and magnified
virtual, erect and diminished
virtual, erect and magnified
virtual, inverted and magnified
Correct answer is D
No explanation has been provided for this answer.