Worksheet: Electric Current and Its effects

# Worksheet: Electric Current and Its effects - Science Class 7

Q.1. True/False
(i) To make a battery of two cells, the negative terminal of one cell is connected to the negative terminal of the other cell.
(ii) When the electric current through the fuse exceeds a certain limit, the fuse wire melts and breaks.
(iii) An electromagnet does not attract a piece of iron.
(iv) An electric bell has an electromagnet.

Q.2. Fill in the blanks.
(i) Longer line in the symbol for a cell represents its ____ terminal.
(ii) The combination of two or more cells is called a ____.
(iii) When current is switched ‘on’ in a room heater, it ____.
(iv) The safety device based on the heating effect of electric current is called a ____.

Q.3. What is electric current?

Q.4. Who discovered magnetic effect of current?

Q.5. Which wire used in electric heater and why?

Q.6.  Is it possible for a wire to melt and break? Why?

Q.7. Who invented electric bulb?

Q.8. Write some uses of battery.

Q.9. What is filament?

Q.10. What is the heating effect of the electric current?

Q.11. What are the uses of heating effect of electric current?

Q.12. Name any two effects of electric current.

Q.13. What is an electric circuit?

Q.14. Explain the symbol of electric cell.

Q.15. Why are fuse wires not used in circuit containing electric cell?

Q.16. Why a fused bulb does not glow?

Q.17. Why should we look for ISI mark on electrical appliances?

Q.18. We could not see element in electrical appliances. Give reason.

Q.19. Sometimes the cells are placed side by side. Then how are the terminals of the cells connected?

Q.20. On what factors does the heat produced in a wire depend?

The document Worksheet: Electric Current and Its effects | Science Class 7 is a part of the Class 7 Course Science Class 7.
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## Science Class 7

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## FAQs on Worksheet: Electric Current and Its effects - Science Class 7

 1. What is electric current and how is it measured?
Ans. Electric current is the flow of electric charge through a conductor. It is measured in units called Amperes (A) using an ammeter, which is connected in series with the conductor to measure the current passing through it.
 2. What are the effects of electric current?
Ans. Electric current can have various effects, such as heating, magnetism, chemical changes, and physiological effects. It can cause a wire to heat up, generate a magnetic field around a wire, trigger chemical reactions in electrolytes, and even cause muscle contractions or electric shocks in living organisms.
 3. How does electric current affect different materials?
Ans. Electric current can affect different materials in different ways. Conductors, such as metals, allow the flow of electric current easily without much resistance. Insulators, on the other hand, do not allow the flow of electric current and act as barriers to the flow of charge. Semiconductors have intermediate behavior, where their conductivity can be controlled by external factors such as temperature or impurities.
 4. What are the safety precautions to be taken while dealing with electric current?
Ans. When dealing with electric current, it is important to take certain safety precautions. Some of these include using insulated tools, wearing safety gloves, avoiding contact with live wires, switching off the power before working on electrical appliances, and using circuit breakers or fuses to prevent overloading or short circuits.
 5. How does electric current affect the human body?
Ans. Electric current can have various effects on the human body depending on its intensity and path. Low levels of electric current may cause tingling or muscle contractions, while higher levels can lead to burns, respiratory problems, and even cardiac arrest. It is essential to be cautious and avoid direct contact with electric current to prevent any harm.

## Science Class 7

142 videos|317 docs|54 tests

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