Science Worksheet (Set 13)
Topic: Electricity and Circuits
Grade: VII
Q1. Answer briefly:
a. Name the alloy which is used to make the heating elements of electrical appliances like an electric heater.
Nichrome
b. Write three factors on which the heating effect of an electric current depends.
– Resistance of the conductor
– Amount of current flowing through the conductor
– Duration for which the current flows
– Amount of current flowing through the conductor
– Duration for which the current flows
c. How does the installation of MCBs contribute to creating a safer environment for electrical appliances and devices?
– MCBs (Miniature Circuit Breakers) automatically disconnect the circuit in case of an overload or short circuit.
– They prevent electrical fires and protect appliances from damage.
– Unlike fuses, MCBs can be reset and used again.
– They prevent electrical fires and protect appliances from damage.
– Unlike fuses, MCBs can be reset and used again.
d. Name the type of cell used in a torch.
Dry cell
e. Name the phenomenon which occurs:
i. When the two naked wires of an electricity supply line touch each other: Short circuit
ii. When too many electrical appliances are connected to a single socket: Overloading
ii. When too many electrical appliances are connected to a single socket: Overloading
f. What is potential difference?
– The difference in electric potential (voltage) between two points in a circuit.
– It is measured in volts (V) and causes electric current to flow.
– It is measured in volts (V) and causes electric current to flow.
g. Who is known as the father of electricity?
Michael Faraday
h. Suppose you have a device with a voltage of 6 volts and a current of 2 amperes flowing through it. Calculate the power consumed by the device.
– Power (P) = Voltage (V) × Current (I)
\[ P = 6V \times 2A = 12W \] Answer: 12 Watts (W)
\[ P = 6V \times 2A = 12W \] Answer: 12 Watts (W)
i. What is the full form of CFL?
Compact Fluorescent Lamp
j. Draw a simple circuit diagram with a closed switch, a bulb, and a battery.
(Diagram should include a battery, a bulb, a switch in the closed position, and connecting wires.)
Q2. Answer the following question:
a. Predict what will happen to the brightness of a light bulb if you add more batteries to a circuit.
– Adding more batteries increases voltage, making the bulb brighter.
– However, too much voltage can cause the bulb to burn out.
– However, too much voltage can cause the bulb to burn out.