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NCERT Solutions for Class 7 Science Chapter 10

"Access expert NCERT solutions for Class 7 Science Chapter 10, focusing on the concept of Electric Current and its Effect.

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NCERT Solutions for Class 7 Science Chapter 10

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  1. Electric Current and its Effect The chapter Electric Current and its Effect explores the fascinating world of electricity, focusing on electric current and its various effects. Here’s a breakdown of the key concepts: Electric Current: ● Imagine tiny charged particles (electrons) flowing in a continuous stream through a conductor like a wire. This flow of electrons is called electric current. ● Measured in amperes (A). Circuits: ● A closed loop that allows electric current to flow is called a circuit. ● Components like wires, switches, and bulbs are connected in a circuit. Effects of Electric Current: ● Heating Effect: When current passes through a wire, it encounters resistance, causing the wire to heat up. This principle is used in appliances like toasters and electric heaters. ● Magnetic Effect: A current-carrying wire creates a magnetic field around it. Electromagnets, which are essential components in motors, generators, and loudspeakers, utilize this effect. ● Lighting Effect: When current flows through a filament in a bulb, it heats up and glows, producing light. This is the basic principle behind incandescent bulbs. ● Chemical Effect: Electric current can cause chemical reactions in certain substances. Electroplating, a process of coating a metal object with another metal, uses this effect. Safety Measures: ● Electricity can be dangerous if not handled properly. It’s crucial to follow safety precautions like using insulated wires, avoiding

  2. overloaded circuits, and not touching electrical appliances with wet hands. Applications: ● Understanding electric current and its effects is essential for the operation of numerous devices in our daily lives, from lights and fans to computers and televisions. NCERT Solutions for Class 7 Science Chapter 10 Exercises 1.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. Ans : 2.Draw the circuit diagram to represent the circuit shown in fig. 14.9.

  3. Ans :

  4. 3.Fig. 14.11 shows four cells fixed on a board. Draw lines to indicate how you will connect their terminals with wires to make a battery of four cells. Ans : 4.The bulb in the circuit shown in fig. 14.13 does not glow. Can you identify the :

  5. Ans :

  6. 5. Name any two effects of electric current. Ams : ● Heat things up (heating effect) – like a toaster. ● Create magnetism (magnetic effect) – used in motors and speakers. 6.When the current is switched on through a wire, a compass needle kept nearby gets deflected from its north-south position. Explain. Ans : When you turn on current in a wire, it acts like a magnet. This magnetic field pushes on the compass needle, making it spin off course from pointing north. The stronger the current, the bigger the nudge. 7.Will the compass needle show deflection when the switch in the circuit shown by fig. 14.15 is closed?

  7. Ans : Incorporating the fact that there’s no battery in the circuit. 8.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 _____________. Ans : (a) positive

  8. (b) battery (c) becomes red hot and emits heat (d) fuse. 9.Write a following statement true and 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. (b) When the electric current through the fuse exceeds a certain limit , the fuse wire melts and breaks. (c) An electromagnet does not aatract a piece of iron. (d) An electric bell has an electromagnet. Ans : (a) False (b) True (c) False (d) True 10. Do you think an electromagnet can be used for separating plastic bags from a garbage heap? Explain. Ans : No , Electromagnets only attract metal, and plastic bags are not metal. So, the magnet wouldn’t pick them up from the trash. 12.Zubeda made an electric circuit using a cell holder shown in fig. 14.16, a switch and a bulb. When she put the switch in the ‘ON’

  9. position, the bulb did not glow. Help Zubeda in identifying the possible defects in the circuit Ans : ● Connect the cells in series: Positive terminal of the first cell to the negative terminal of the second (and so on). ● Ensure the switch is closed: This allows current to flow. ● Check that the bulb isn’t fused: A broken filament means no glow. 13. In the circuit shown in fig. 14.17.

  10. Would any of the bulb glow when the switch is in the ‘OFF’ position?What will be the order in which the bulbs A, B and C will glow when the switch is moved to the ‘ON’ position? Ans : Switch Off: No power, no glow (bulbs are off). Switch On (Series Circuit): Bulbs A, B, C glow one after the other (not all at once).

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