मराठी

Paheli does not have a night lamp in her room. She covered the bulb of her room with a towel in the night to get dim light. Has she taken the right step? Give one reason to justify your answer. - Science

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प्रश्न

Paheli does not have a night lamp in her room. She covered the bulb of her room with a towel at the night to get dim light. Has she taken the right step? Give one reason to justify your answer.

कारण सांगा
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उत्तर

No, the towel may burn due to the heat produced by the bulb. Besides, it will also result in the wastage of electric energy. She could have used a lamp shade.

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  या प्रश्नात किंवा उत्तरात काही त्रुटी आहे का?
पाठ 14: Electric Current and Its Effects - VERY SHORT ANSWER QUESTIONS [पृष्ठ ७७]

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एनसीईआरटी एक्झांप्लर Science [English] Class 7
पाठ 14 Electric Current and Its Effects
VERY SHORT ANSWER QUESTIONS | Q 10. | पृष्ठ ७७

संबंधित प्रश्‍न

For the coil in the diagram below, when the switch is pressed:

(a) what is the polarity of end A?
(b) which way will the compass point then?    


 What device reverses the current?


When the switch S is closed in the figure given below, the pointer of the galvanometer moves to the right.  

 

If S is kept closed, will the pointer:

(a) return to zero?
(b) stay over on the right?
(c) move to the left and stay there
(d) move to and fro until S is opened


In the Activity shown below, how do we think the displacement of rod AB will be affected if

  1. current in rod AB is increased
  2. a stronger horse-shoe magnet is used
  3. length of the rod AB is increased?
  • Take a small aluminium rod AB (of about 5 cm). Using two connecting wires suspend it horizontally from a stand, as shown in Fig.
  • Place a strong horse-shoe magnet in such a way that the rod lies between the two poles with the magnetic field directed upwards. For this put the north pole of the magnet vertically below and south pole vertically above the aluminium rod (Fig.).
  • Connect the aluminium rod in series with a battery, a key and a rheostat.
  • Now pass a current through the aluminium rod from end B to end A.
  • What do you observe? It is observed that the rod is displaced towards the left. You will notice that the rod gets displaced.
  • Reverse the direction of current flowing through the rod and observe the direction of its displacement. It is now towards the right.
  • Why does the rod get displaced?


A current-carrying rod, AB, experiences a force perpendicular to its length and the magnetic field. Support for the magnet is not shown here, for simplicity.


Observe the following diagram and choose the correct alternative:


A soft iron bar is introduced inside the current-carrying solenoid. The magnetic field inside the solenoid ____________.


In the arrangement shown in Figure  there are two coils wound on a non-conducting cylindrical rod. Initially the key is not inserted. Then the key is inserted and later removed. Then


Why do we cover plug pin holes which are within the reach of children with cellotape or a plastic cover when not in use?


An electric bell contains an ______, consisting of coils of insulated wire wound around
iron rods.


A rectangular loop ABCD carrying a current I is situated near a straight conductor XY, such that the conductor is parallel to the side AB of the loop and is in the plane of the loop. If a steady current I is established in the conductor as shown, the conductor XY will ______.


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