Ask a Doubt
Request a call back

Join NOW to get access to exclusive study material for best results

CBSE Class 12-science Answered

Please solve the following question using Kirchoff's current law and Kirchoff's voltage law asap. :))
question image
Asked by mfirdous111 | 24 Nov, 2020, 12:05: AM
answered-by-expert Expert Answer
Figure shows the current passing through each resistor. 
 
Since all resistors are in kΩ, we consider all currents in mA
 
By applying Kirchoff's voltage law (KVL) we get , 8 I1 + 4 I2 = 12 V  or  2 I1 + I2 = 3  .....................(1)
 
In loop-2, by applying KVL , we get , 10 I4 + 5 I5 = 4 I2 ..................(2)
 
In loop-3 , by applying KVL , we get , 18 I7 = 5 I5 ........................(3)
 
At node-Q , if we apply Kirchoff's Current law ( KCL ) , we get , I4 = I5 + I7 ...............(4)
 
Using eqn.(4) and eqn.(3), we rewrite eqn.(2) as 10 I5 + 28 I7 = 4 I2  ...................(5)
 
Using eqn.(3) , we rewrite eqn.(5) as ,  64 I7 = 4 I2   or   I7 = (1/16) I2 .................(6)
 
Using eqn.(3) , we get I5 = (18/5) I7 = (18/5) (1/16) I2 
 
Hence we get  I5 = (9/40) I2  ...........................(7)
 
From eqn.(4), we get , I4 = [ (9/40) + (1/16) ] I2 = (23/80) I2 .......................(8)
 
At node-P , if we apply Kirchoff's Current law ( KCL ) , we get , I1 = I2 + I4 ...............(9)
 
Let us rewrite eqn.(1) , using eqn.(9) as , 3I2 + 2I4 = 3   
 
  3 I2 + 2 (23/80) I2 = ( 143/40 ) I2 = 3     or   I2 = ( 120/143 )  = 0.839 mA   .....................(10)
 
Hence from eqn.(1) , we get I1 = (3/2) - (1/2) I2 = (3/2) - (1/2)(0.839) = 1.080 mA   ................(11)
 
Current I4 = (23/80) ( 0.839) = 0.241 mA
 
Current I5 = (9/40) ( 0.839) = 0.189 mA
 
Current I7 = (1/16) (0.839) = 0.052 mA
 
By knowing all the currents passing in the circuit , it is possible to get voltage across each resistor.
Answered by Thiyagarajan K | 24 Nov, 2020, 10:41: AM

Concept Videos

Multiple Choice Questions Practice Test Subjective Questions Webinar Subjective Questions Pre Board Assessment
Answered Unanswered My Questions My Answers
CBSE 12-science - Physics
answer
question image
Asked by r01raunak | 23 May, 2023, 10:24: AM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 12-science - Physics
Kirchhoff law
Asked by komalbrar0987 | 17 May, 2023, 06:15: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 12-science - Physics
obtain the lens formula in case of concave lens
Asked by marvellouskyndiah | 17 May, 2023, 08:07: AM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 12-science - Physics
semi conductor
Asked by Abhishek | 23 Mar, 2023, 08:37: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 12-science - Physics
Soft iron is used to make the core of transformer because of it's.....  a) low coercivity and low retentivity b) high corecivity and low retentivity Chose correct option and give reason. 
Asked by Jayashri | 06 Mar, 2023, 06:47: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 12-science - Physics
Please answer this question. Draw a graph showing the variation of binding energy per nucleon as a function of mass number A. The binding energy per nucleon for heavy nuclei (A > 170) decreases with the increase in mass number. Explain.
Asked by varma.renu9481 | 06 Mar, 2023, 05:44: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 12-science - Physics
Please answer below question from 2023 board paper:  
question image
Asked by prachis14 | 06 Mar, 2023, 04:49: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 12-science - Physics
An inductor, a capacitor and a resistor are connected in series across an ac source of voltage. If the frequency of the source is decreased gradually. the reactance of: (a) both the inductor and the capacitor decreases. (b) inductor decreases and the capacitor increases. (c) both the inductor and the capacitor increases. (d) inductor increases and the capacitor decreases.
Asked by paresh0311 | 06 Mar, 2023, 04:42: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 12-science - Physics
Answer this:  Assertion (A): When radius of a circular loop carrying a steady current is doubled, its magnetic moment becomes four times.  Reason (R): The magnetic moment of a circular loop carrying a steady current is proportional to the area of the loop.  Select the correct answer from the codes (a), (b), (c) and (d) as given belote.  (a) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).  (b) Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).  (c) Assertion (A) is true, but Reason (R) is false.  (d) Assertion (A) is false and Reason (R) is also false.
Asked by anubhutiupadhaya | 06 Mar, 2023, 04:23: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 12-science - Physics
Please answer this.  What is meant by the term 'displacement current'? Briefly explain how this current is different from a conduction current.
Asked by sagarmishra | 06 Mar, 2023, 04:07: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
My Class Videos Tests ₹ Plans Ask a Doubt