Advertisements
Advertisements
Question
Calculate the effective resistance across AB?
Advertisements
Solution
5 Ω and 4Ω are in series
∴ R1 = (5 + 4)Ω = 9Ω
Now, 9Ω and 3Ω are in parallel
`therefore R_2 = (9 xx 3)/(9+3)=9/4Ω`
Now, 2 8Ω and R2 are in series
`therefore R_3 = 8 +9/4 =41/4 Ω= 10.25Ω`
APPEARS IN
RELATED QUESTIONS
When a 12 V battery is connected across an unknown resistor, there is a current of 2.5 mA in the circuit. Find the value of the resistance of the resistor.
A low voltage supply from which one needs high currents must have very low internal resistance. Why?
The graph between V and I for a conductor is a straight line passing through the origin.
- Which law is illustrated by such a graph?
- What should remain constant in a statement of this law?
A metal sphere is kept on an insulting stands. A negatively charged rod is brought near it, then the sphere is earthed as shown. On removing the earthing, and taking the negatively charged rod away, what will be the nature of charge on the sphere? Give reason for your answer.
What are non-ohmic conductors? Give one exmaple. Draw a current-voltage graph for a non-ohmic conductor.
SI unit of resistance is:
Define temperature coefficient of resistance.
Write a short note on superconductors?
Two cells of same emf E but internal resistance r1 and r2 are connected in series to an external resistor R (Figure). What should be the value of R so that the potential difference across the terminals of the first cell becomes zero.
Let the resistance of an electrical device remain constant, while the potential difference across its two ends decreases to one fourth of its initial value. What change will occur in the current through it? State the law which helps us in solving the above stated question.
