हिंदी

Identify the figure and give its use.

Advertisements
Advertisements

प्रश्न

Identify the figure and give its use.

Identify a figure and write one use of it:

वर्गीकरण करो
लघु उत्तरीय
Advertisements

उत्तर

  • Figure: MCB (Miniature Circuit Breaker)
  • Uses: An MCB is a device which functions as a fuse but does not require replacement. MCB falls down to break the circuit when a heavy amount of current flows through it. Once the fault is rectified, the MCB is reset.
shaalaa.com
  क्या इस प्रश्न या उत्तर में कोई त्रुटि है?
अध्याय 4: Effects of electric current - Exercises [पृष्ठ ६१]

APPEARS IN

बालभारती Science and Technology Part 1 [English] Standard 10 Maharashtra State Board
अध्याय 4 Effects of electric current
Exercises | Q 11.2 | पृष्ठ ६१

संबंधित प्रश्न

Why does the cord of an electric heater not glow while the heating element does?


An electric iron of resistance 20 Ω takes a current of 5 A. Calculate the heat developed in 30 s.


Why are the conductors of electric heating devices, such as bread-toasters and electric irons, made of an alloy rather than a pure metal?


The safety device based on the heating effect of electric current is called a ______.


Write Joule's law of heating.


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?


Write down the formula for the heat produced when a current I is passed through a resistor R for time t.


A resistance of 25 Ω is connected to a 12 V battery. Calculate the heat energy in joules generated per minute.


 How much heat will an instrument of 12 W produce in one minute if it is connected to the heat produced by it?  


The current passing through a room heater has been halved. What will happen to the heat produced by it?


Two exactly similar heating resistances are connected (i) in series, and (ii) in parallel, in two different circuits, one by one. If the same current is passed through both the combinations, is more heat obtained per minute when they are connected in series or when they are connected in parallel? Give reason for your answer.


Give Scientific reason
In the electric equipment producing heat e.g. iron, electric heater, boiler, toaster etc, an alloy such as Nichrome is used, not pure metals.


Solve the following example.

Two tungsten bulbs of wattage 100 W and 60 W power work on 220 V potential difference. If they are connected in parallel, how much current will flow in the main conductor? 


In an electric bulb, coil of _______ metal is used.


Which metal is used to make the filament of an electric bulb?


What is overloading?


Which of the following is correct?


Mark the correct choice

  1. Assertion: Electric appliances with a metallic body have three wire connections.
  2. Reason: Three-pin connections reduce the heating of the connecting wires.

An electric iron consumes energy at the rate of 420 W when heating is at the maximum rate and 180 W when heating is at the minimum rate. The applied voltage is 220 V. What is the current in each case?


Which of the following gases are filled in electric bulbs?


An electric kettle consumes 1 kW of electric power when operated at 220 V. A fuse wire of what rating must be used for it?


B1, B2 and B3 are three identical bulbs connected as shown in Figure. When all the three bulbs glow, a current of 3A is recorded by the ammeter A.

  1.  What happens to the glow of the other two bulbs when the bulb B1 gets fused?
  2. What happens to the reading of A1, A2, A3 and A when the bulb B2 gets fused?
  3. How much power is dissipated in the circuit when all the three bulbs glow together?

 


An electric cell produces electricity from the ______ ______ in it.


Unscramble the following words:

SFEU


An electric fuse has a body made of ceramic and two points for connecting the fuse wire.


Copper wire offers very little ______ and does not get heated up quickly.


Assertion: A current-carrying wire should be charged.
Reason: The current in a wire is due to the flow of free electrons in a definite direction.


Name a few appliances which work on the basis of the heating effect of current.


A student boils water in an electric kettle for 20 minutes. Using the same mains supply he wants to reduce the boiling time of water. To do so should he increase or decrease the length of the heating element? Justify your answer.


An electrochemical cell converts ______ energy into ______ energy.


The electric fuse works on the Joule heating principle.


Define the following:

Electrolyte


An electric kettle consumes 1 kW of electric power when operated at 220 V. A fuse wire of what rating must be used for it?


An electric kettle of 2 kW is used for 2h. Calculate the energy consumed in 

  1. kilowatt hour and
  2. joules.

An electric iron of resistance 20 Ω draws a current of 5 A. The heat developed in the iron in 30 seconds is ______.


Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×