NCERT Solutions for Class 7th Science
Chapter 14. Electric Current and its Effects
Ques: How are two or more than two cells connected?
Ans: For connecting two or more than two cells, positive terminal of one cell is connected to negative terminal of the other cell.
Ques: What is battery?
Ans: Positive terminal of one cell is connected to negative terminal of the next cell, such a connection of two or more than two cells is known as battery.
Ques: What do you understand by heating effect of the electric current?
Ans: The wire gets hot when an electric current passes through it. This is the heating effect of the electric current.
Ques: Name two devices that work on the basis of heating effect of the electric current.
Ans: Electric iron and heater.
Ques: What material is the element made of in electric heater?
Ques: What is fuse ? Give two reasons for connecting it in electric circuits.
Ans: Safety device using in electric circuits is called as fuse.
(i) It prevents the costly instruments connecting in electric circuit during overloading and short circuit.
(ii) It prevents against possibility of fire and damages of circuits.
Ques: What is overloading?
Ans: It begins to flow excess electric current in a circuit due to connect many devices to the single socket. This is known as overloading.
Ques: What is cell?
Ans: The cell is a device in which produced electric current by chemical changes.
Ques: Write the order in which cells of torch is connected.
Ans: The cells of torch is connected in series.
Ques: Name any two insulators.
Ans: rubber and plastic.