67) In an electric circuit, the device used to prevent damage to the electrical appliances due to overloading is:

A) electromagnet
B) electric fuse
C) battery
D) electric cell

68) Which of the following is not an alloy?

A) Constantan
B) Manganin
C) Nichrome
D) Iron

69) Identify the wrong statement among the following:

A) Magnetic field lines are closed curves
B) Inside the magnet, the direction of field lines is from north pole to south pole
C) The magnetic field is stronger where the magnetic field lines are crowded
D) Magnetic field lines do not intersect with each other

70) SI unit of electrical resistivity is

A) Ωm
B) Ω/m
C) m/Ω
D) Ωm²

71) Which of the following is an insulator?

A) Copper
B) Silver
C) Aluminium
D) Rubber