Kerala SCERT Class 7 Science Chapter 5 When Current Flows Question Answer Solution Here. Kerala Board Class 7 Students can find Here 5th Chapter When Current Flows Notes provide by our Teacher. Important Question Answer from Chapter 5 When Current Flows.
- Board- Kerala Board.
- Class – 7.
- Subject – Science Part 1
- Chapter – 5.
- Chapter Name – When Current Flows.
- Topic – Question Answer Solution.
Multiple choice questions.
(1) Substances that conduct electricity are called
a) Conductors
b) Insulators
c) Both
d) None.
(2) Substances which do not conduct electricity are called
a) Conductors
b) Insulators
c) Both
d) None.
(3) These are types of wires
a) Multistranded wire
b) Laminated wire
c) Service wire
d) Non-insulated wire
e)All the above.
(4) Electric circuit consist of
a) Source of electricity
b) Device that uses electricity
c) Wire that conducts electricity
d)All the above.
(5) Types of switches are
a) ordinary switch
b) bell switch
c) press button switch
d) D P switch
e)All the above.
(6) These are devices that make use of electromagnets
a) Electric fan
b) Electric bell
c) Electric motor
d) All the above.
Questions and answers.
(1) What is safety Fuse?
ANS: Safety fuse is a device used in circuits as a precaution to protect the circuit and electric devicesfrom damage caused by the flow of excess current.
(2) What is MCB (Miniature Circuit Breaker)?
ANS: MCB is used instead of safety fuse in houses. This device breaks a circuit whenever there is an excessive flow of current.
3) What Christian Oersted discovered?
ANS: The scientist Christian Oersted discovered that a magnetic field is produced around a current-carrying conductor.
Short questions and answers.
(1) Which are situations when electricity is wasted in house?
ANS: situations are given below:
i) Bulb and fan switched on even when there is no one in the room.
ii) TV switched on even when there is no one to watch it.
iii) Bulbs switched on even during day time.
iv) Refrigerator left open.
(2) Which are the situations leading to an electric shock?
ANS: situations are given below:
i) Operating a switch with a wet hand.
ii) Removing plug pins when the switch is on.
iii) Using wires without insulation
iv) Changing bulb when the switch is on.
(3) What immediate action should we take to save a person who gets electric shock?
ANS: Actions given below:
i) The first thing to do is to cut off the electric connection. For this, either switch off the electric supply or remove the fuse.
ii) The person should be taken to the nearest hospital immediately if the shock is severe.
iii) If the heart beat ceases, immediately place your palms one over the other on the person’s chest and start pressing down and then release. Continue this process until the heart starts beating on its own.
(4) How the torch bulb glows?
ANS: The procedure given below:
i) Prepare an arrangement to light a bulb using two torch cells, one torch bulb and two pieces of copper wires.
ii) A path is prepared for current to flow from one terminal to the other terminal of the torch cells through a copper wire and a bulb.
Iii) In this way bulb glows.