Heat and Elec quiz of SPJ

The direct transfer of heat from one substance to another that is touching is referred to as

• Convection

• Convection currents

• radiation

• conduction

Inside an air-conditioned room, metallic objects generally feel cooler to touch than wooden objects. Why is this so?

• The human body resembles wood more closely

• Heat tends to flow from metal to wood

• Wood contains more heat than a metal of the same mass

• Metal heats up and cools down faster than wood.

Which of the following explains why the lady can to hold the handle of the pan with her bare hands?

I. The handle is made of good insulator of heat.

II. The handle has low thermal conductivity.

III. The handle has high thermal expansion.

• I and II only

• I and III only

•  II and III only

•  I, II, and III

Which of the following methods of heat transfer is NOT taking place in the given situation.

• Conduction

• Convection

• Radiation

• None of the above

A charge cannot be created nor destroyed but can be transferred from one material to another.

• The law of Conservation of charge

• Electrostatic law

• Law of conservation of mass

• Law of electricity

The figure shows three pairs of plates. The electrostatic force between the plates is shown for two of the pairs.  If B is negative, what is the charge of A? and what kind of force exists in the third pair?

• negative, attractive

• negative, repulsive

• positive, attractive           

• positive, repulsive

It take place due to the vibrating and colliding particles of objects that are in contact

• Conduction

• Convection

• Radiation

• None of them

What will happen when two like charges are brought together?

• They will repel each other

• They will neutralize each other

• They will attract each other.

• They will have no effect on each other.

Which of the following describes the usual way by which a material can gain a positive charge?

• By gaining protons 

• By gaining electrons

• By losing protons   

• By losing electrons

Which is not an insulator?

• Wood

• Rubber

• Hair

• Copper