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प्रश्न
Find the odd one out and give its explanation.
पर्याय
Tungsten
Nichrome
Aluminium
Iron
उत्तर
Nichrome
Explanation-
Nichrome is an alloy used for making wires, while others are soft metals.
APPEARS IN
संबंधित प्रश्न
Why does the cord of an electric heater not glow while the heating element does?
An electric heater is connected to the 230 V mains supply. A current of 8 A flows through the heater.
(a) How much charge flows around the circuit each second?
An electric room heater draws a current of 2.4 A from the 120 V supply line. What current will this room heater draw when connected to 240 V supply line?
What is nichrome? State its one use.
Give two reasons why nichrome alloy is used for making the heating elements of electrical appliances.
Why are the coils of electric irons and electric toasters made of an alloy rather than a pure metal?
Write down the formula for the heat produced when a current I is passed through a resistor R for time t.
Explain why, the current that makes the heater element very hot, only slightly warms the connecting wires leading to the heater.
Which of the following characteristic is not suitable for a fuse wire?
(a) thin and short
(b) thick and short
(c) low melting point
(d) higher resistance than rest of wiring
How does the wire in the filament of a light bulb behave differently to the other wires in the circuit when the current flows?
What property of the filament wire accounts for this difference?
An electric iron is connected to the mains power supply of 220 V. When the electric iron is adjusted at 'minimum heating' it consumes a power of 360 W but at 'maximum heating' it takes a power of 840 W. Calculate the current and resistance in each case.
Give Scientific reason.
In practice, the unit kWh is used for the measurement of electrical energy, rather than joule.
Why does tungsten metal used to make solenoid type coil in an electric bulb?
These days when current in the circuit suddenly increases _______ switches are used.
What is the heating effect of electric current?
Live wire and neutral wires have a 220 V potential difference.
Name some devices that run using heat effect of electric current
Mark the correct choice
- Assertion: Electric appliances with a metallic body have three wire connections.
- Reason: Three-pin connections reduce the heating of the connecting wires.
An electric bulb is connected to a 220 V generator. The current is 0.50 A. What is the power of the bulb?
Which of the following gases are filled in electric bulbs?
Three incandescent bulbs of 100 W each are connected in series in an electric circuit. In another circuit another set of three bulbs of the same wattage are connected in parallel to the same source.
- Will the bulb in the two circuits glow with the same brightness? Justify your answer.
- Now let one bulb in both the circuits get fused. Will the rest of the bulbs continue to glow in each circuit? Give reason.
An electric component used as a safety device is electric circuit is ______.
Name two electric devices for each where
(i) the heating effect of current is used and
(ii) the magnetic effect of current is used.
An MCB can be used instead of a fuse in an electrical circuit.
What are the uses of electromagnets?
Explain the working of an electric fuse.
______ wire is used in the filament of the bulbs.
Name the effect of the current responsible for the glow of the bulb in an electrical circuit.
A trip switch is a ______ safety device.
A fuse is used in an electric circuit to stop high currents flowing through the circuit.
The electric fuse works on the Joule heating principle.
Tara, after completing her exams, went to her grandmother's house along with her younger brother Rahul. One day, Rahul came home after playing and switched on the fan and air conditioner. At the same time, his grandmother was preparing a milkshake for him using a mixer. Suddenly, they heard a big sound and the electricity of the house got shut down. Tara is called an electrician. He said the main reason for supply to shut down was overloading.
- What is overloading?
- Is overloading and short the same? When does short-circuiting take place?
- How can the effects of overloading be avoided?
Find the odd one out.
In the electric equipment producing heat like iron, electric heater, boiler, toaster etc., an alloy such as nichrome is used, not pure metals.
Anannya responded to the question: Why do electrical appliances with metallic bodies are connected to the mains through a three-pin plug, whereas an electric bulb can be connected with a two-pin plug?
She wrote: Three-pin connections reduce heating of connecting wires.
- Is her answer correct or incorrect? Justify.
- What is the function of a fuse in a domestic circuit?
