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Electric current and it’s effect

Do you think an electromagnet can be used for separating plastic bags
from a garbage heap? Explain.

04/11/2024

Science

7th

Electric current and it’s effect

Mark ‘T’ if the statement is true and ‘F’ if it is false:
(a) To make a battery of two cells, the negative terminal of one cell is
connected to the negative terminal of the other cell. (T/F)
(b) When the electric current through the fuse exceeds a certain limit,
the fuse wire melts and breaks. (T/F)
(c) An electromagnet does not attract a piece of iron. (T/F)
(d) An electric bell has an electromagnet. (T/F)

04/11/2024

Science

7th

Electric current and it’s effect

Fill in the blanks:
(a) Longer line in the symbol for a cell represents its terminal.
(b) The combination of two or more cells is called a .
(c) When current is switched ‘on’ in a room heater, it .
(d) The safety device based on the heating effect of electric current is
called a .

04/11/2024

Science

7th

Electric current and it’s effect

When the current is switched on through a wire, a compass needle kept
nearby gets deflected from its north-south position. Explain.

04/11/2024

Science

7th

Electric current and it’s effect

Name any two effects of electric current.

04/11/2024

Science

7th

Electric current and it’s effect

Draw in your notebook the symbols to represent the following
components of electrical circuits: connecting wires, switch in the ‘OFF’
position, bulb, cell, switch in the ‘ON’ position, and battery

04/11/2024

Science

7th

Motion and time

Which of the following relations is correct?
(i) Speed = Distance × Time (ii) Speed =
Distance
Time
(iii) Speed =
Time
Distance (iv) Speed =
1
Distance Time

04/11/2024

Science

7th

Motion and time

A car moves with a speed of 40 km/h for 15 minutes and then with a
speed of 60 km/h for the next 15 minutes. The total distance covered by
the car is:
(i) 100 km (ii) 25 km
(iii) 15 km (iv) 10 km

04/11/2024

Science

7th

Motion and time

The basic unit of speed is:
(i) km/min (ii) m/min
(iii) km/h (iv) m/s

04/11/2024

Science

7th

Motion and time

Show the shape of the distance-time graph for the motion in the
following cases:
(i) A car moving with a constant speed.
(ii) A car parked on a side road.

04/11/2024

Science

7th