हिंदी

These days when current in the circuit suddenly increases _______ switches are used.

Advertisements
Advertisements

प्रश्न

These days when current in the circuit suddenly increases _______ switches are used.

विकल्प

  • MCA

  • MCC

  • MCD

  • MCB

MCQ
रिक्त स्थान भरें
Advertisements

उत्तर

These days when current in the circuit suddenly increases MCB switches are used.

shaalaa.com
  क्या इस प्रश्न या उत्तर में कोई त्रुटि है?
अध्याय 4: Effects of electric current - Choose the correct option. [पृष्ठ ४]

APPEARS IN

एससीईआरटी महाराष्ट्र Science and Technology Part 1 [English] Standard 10 Maharashtra State Board
अध्याय 4 Effects of electric current
Choose the correct option. | Q 6. | पृष्ठ ४

संबंधित प्रश्न

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


Why is the tungsten used almost exclusively for filament of electric lamps?


How does the resistance of a wire vary with its area of cross-section?


When current is switched ‘on’ in a room heater, it ______.


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?


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?


How does the resistance of a wire vary with its: 

 diameter? 

 


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


Explain why, the current that makes the heater element very hot, only slightly warms the connecting wires leading to the heater.


Derive the expression for the heat produced due to a current 'I' flowing for a time interval 't' through a resistor 'R' having a potential difference 'V' across its ends. With which name is this relation known?


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


The heat produced by passing an electric current through a fixed resistor is proportional to the square of:  

(a) magnitude of resistance of the resistor
(b) temperature of the resistor
(c) magnitude of current
(d) time for which current is passed


Give Scientific reason.

In practice, the unit kWh is used for the measurement of electrical energy, rather than joule.


An electric iron of 1100 W is operated for 2 hrs daily. What will be the electrical consumption expenses for that in the month of April? (The electric company charges Rs 5 per unit of energy).


Statement 1 : Electric current ( flow of electrons ) creates heat in the resistor.
Statement 2 : Heat in the resistor is created according to the rule of energy conservation.
Explain Statement 1 with the help of Statement 2.


Name the factors on which the heat produced in a wire depends when current is passed in it, and state how does it depend on the factors stated by you.


Compute the heat generated while transferring 96000 coulombs of charge in two hours through a potential difference of 40 V.


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


The electricity bill specifies the usage in _______.


A coil of an alloy _______ is used in electric heater cooker as a resistor.


Name some devices that run using heat effect of electric current


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.

Which of the following gases are filled in electric bulbs?


How does use of a fuse wire protect electrical appliances?


Why is parallel arrangement used in domestic wiring?


What is Joule’s heating effect? How can it be demonstrated experimentally? List its four applications in daily life.


Can we use the same fuse in a geyser and a television set? Explain.


Match the following

1. Bulb a. Conductor
2. Electroplating b.

Insulator

3. Pure water c.  Heating effect of current
4. Salt solution d. Chemical effect of current

What is a trip switch?


An electrochemical cell converts ______ energy into ______ energy.


Define the following:

Electrolyte


Two students decided to investigate the effect of water and air on iron object under identical experimental conditions. They measured the mass of each object before placing it partially immersed in 10 ml of water. After a few days, the object were removed, dried and their masses were measured. The table shows their results.

Student Object Mass of Object
before Rusting in g
Mass of the coated
object in g
A Nail 3.0 3.15
B Thin plate 6.0 6.33

What might be the reason for the varied observations of the two students?


In a set up the students coated iron nails with zinc metal and noted that, iron nails coated with zinc prevents rusting. They also observed that zinc initially acts as a physical barrier, but an extra advantage of using zinc is that it continues to prevent rusting even if the layer of zinc is damaged. Name this process of rust prevention and give any two other methods to prevent rusting.


An electric iron is rated 220 V, 2 kW. If the iron is used for 3h daily find the cost of running it for one week if it costs ₹ 4.25 per kWh.


Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×