LAQ for Chapter 3 Electricity: Circuits and their Components Class 7 Science NCERT

Answer

• An electric cell is a source of electrical energy. 
• It has two terminals: a positive (+) terminal and a negative (-) terminal. 

Electric Cell
• These two terminals are connected by a circuit. 
• Inside the cell, a chemical reaction occurs between the materials inside the cell. 
• This chemical reaction releases electrons (tiny charged particles) that move from the negative terminal to the positive terminal, creating an electric current. 
• This current flows through the wires of the circuit and powers the devices connected to it, like lamps, radios, clocks, or remote controls. 
• The flow of current from the electric cell provides the energy needed for these devices to work. 

Answer

• An LED lamp is different from traditional lamps like incandescent or fluorescent lamps. 
• It does not have a filament, but instead uses a special material called a diode to produce light. 
• The LED lamp has two terminals: one longer (positive terminal) and one shorter (negative terminal). 
• The lamp is designed to glow when the positive terminal of the lamp is connected to the positive side of a battery or power source, and the negative terminal is connected to the negative side. 
• When current flows through the LED, it moves in only one direction because LEDs only work when the current is going from the positive to the negative terminal. 
• This makes LEDs more efficient, meaning they use less energy to produce light and last longer than regular bulbs. 
• Since there is no filament, LED lamps are less likely to break or burn out, which makes them more durable. 

Answer

• A simple electrical circuit consists of a few key parts: an electric cell (like a battery), a lamp, and wires.
• When the switch in the circuit is in the "on" position, it allows electricity to flow from the positive terminal of the cell through the wires and into the lamp.
• Inside the lamp, there is a filament (a thin wire), and when electricity passes through the filament, it heats up and starts to glow.
• This produces light.
• If the switch is turned off, the circuit becomes incomplete, and the electric current cannot flow, so the lamp will not glow.
• The switch is used to either allow or stop the flow of electricity, controlling when the lamp is on or off.

Answer

n an electrical circuit, conductors and insulators play important roles:

Conductors vs Insulators
• Conductors are materials that allow electricity to flow through them easily. Metals like copper, silver, and aluminum are good conductors. They are used in the wires that connect different parts of an electrical circuit because they let the electric current pass through them without resistance.
• Insulators, on the other hand, are materials that do not allow electricity to flow. They protect us from electric shocks. Common insulators include plastic, rubber, and wood. These materials are used to cover wires, make electrical switches, and create plug tops. They make sure that the current stays inside the wires and does not harm us or cause short circuits.

In simple terms, conductors let electricity flow, while insulators keep electricity safely contained within the circuit.

Answer

• A switch is an important device in electrical circuits because it helps control the flow of electricity.
• The switch acts like a gate for the electric current.
• When the switch is in the "on" position, it closes the circuit, allowing electricity to flow through and power the connected device, such as a lamp, fan, or television.
• This makes the device work.
• When the switch is in the "off" position, it opens the circuit, which stops the flow of electricity.
• As a result, the device is turned off.
• Switches are essential for turning electrical devices on and off safely and efficiently.
• Without switches, you would have to disconnect wires every time you want to turn something off, which would be impractical and unsafe.
• Therefore, switches make electrical circuits safer and easier to use, as they give us control over the devices that run on electricity.