a.

Positive charge means deficit electrons

b.

Negative charge means excess of electrons

c.

Electric current means movement of electrons

d.

All of the above

a.

Refraction of light

b.

Reflection of light

c.

Defraction of light

d.

Rectilinear propagation of light

a.

Low density

b.

Low boiling point

c.

High specific heat capacity

d.

Low freezing point

a.

Convection and radiation

b.

Convection and conduction

c.

Conduction and radiation

d.

Radiation only