Q28 of 41 Page 461

Find the value of current I in the circuit given below:

Resistors across AC and DE are in parallel i.e. RAC and RDE are in parallel.

So



⇒


⇒


⇒


Now R’p and RBC are I series.


R’s = R’p + RBC


⇒ R’s = 15 + 15 = 30Ω.


Again, RAB and R’s are in parallel.




⇒


⇒ R’’p =


Equivalent resistance of the above circuit is 10Ω.


Now, current flowing through the circuit is


I =


The value of current is 0.3A


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In the given circuit, connect a nichrome wire of length ‘L’ between points X and Y and note the ammeter reading.


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(ii) State the changes that are observed in the ammeter reading if we double the area of cross-section without changing the length in the above experiment. Justify your answer in both the cases.

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Shushant was doing an experiment by using an ammeter. Unfortunately, it fell from his hand and broke. Fearing the scolding of teacher, his group mates advised him not to tell the teacher, but he told her. On listening to him patiently, the teacher did not scold him as it was just and accident and used the opportunity to show the whole class the internal structure of ammeter.

What are the values displayed by Shushant?