61) For the children below the age of 10 years, the value of least distance of distinct vision is about

A) 7-8 cm
B) 25 cm
C) 60 cm
D) 2.27 cm

62) Pick the false statement on the magnetic field lines

A) they are imaginary lines
B) they are two dimensional
C) they are closed loops
D) they never intersect with each other

63) The SI units of magnetic flux and magnetic flux density respectively are

A) coulomb and water
B) coulomb and tesla
C) weber and tesla
D) weber and ampere

64) The development of electromagnetism lead to the invention of

A) electric bulb
B) electric geyser
C) battery
D) dynamo

65) The magnetic flux passing through a unit area perpendicular to the field is called

A) magnetic flux density
B) magnetic moment
C) magnetic pole strength
D) electromotive force