2. Make four electromagnets with 20, 40, 60 and 80 turns. Connect them one by one to a battery of 2 cells. Bring the electromagnet near a box of pins. Count the number of pins attracted by it. Compare the strengths of the electromagnets.
Answer: The activity can be carried out as follows:
Aim: To compare the strengths of electromagnets with 20, 40, 60 and 80 turns.
Materials Required: Insulated wire (four pieces), four iron nails, compass needle, two electric cells, switch, box of pins.
Procedure:
(i) Take four pieces of insulated wire and wrap them 20, 40, 60 and 80 times around four iron nails.
(ii) Connect the free ends of the wire to the terminals of 2 cells in each case.
(iii) Put the switch to ‘ON’ and one by one bring the four electromagnets near a box of pins.
(iv) Count the number of pins attracted by each magnet and based on that make conclusions about the strengths of the four electromagnets.
Observations and Conclusions: The electromagnet with 80 turns attracts the largest number of pins followed by the one with 60 turns, then 40 turns and finally the one with 20 turns attracts the least number of pins. We conclude that higher the number of turns of wire, higher the strength of the electromagnet.
“Make four electromagnets with 20, 40, 60 and 80 turns. Connect them one by one to a battery of 2 cells. Bring the electromagnet near a box of pins. Count the number of pins attracted by it. Compare the strengths of the electromagnets.” – Solved.
Related Links:
Solution to Extended Learning Problem 1
Solution to Extended Learning Problem 2
Solution to Extended Learning Problem 3
Solution to Extended Learning Problem 4
Solution to Activity 10.1
Solution to Activity 10.2
Solution to Activity 10.3
Solution to Activity 10.4
Solution to Activity 10.5
Solution to Activity 10.6
