Advertisements
Advertisements
Question
A resistance of 40 ohms and one of 60 ohms are arranged in series across 220 volt supply. Find the heat in joules produced by this combination of resistances in half a minute.
Advertisements
Solution
The net resistance of the circuit, R = 40 + 60 = 100
Time for which current is passed = `1/2 minute =30s` minute = 30 s
Current in the circuit = `V/R=220/100 =2.2 A`
Heat produced = I2Rt = (2.2)2 (100) (30) = 4.84 x 100 x 30 = 14520 J
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.
Is Ohm’s law universally applicable for all conducting elements? If not, give examples of elements which do not obey Ohm’s law.
Write the formula of resistivity
Name the law which is illustrated by the above V−I graph.
Keeping the p.d. constant, the resistance of a circuit is halved. The current will become:
(a) one-fourth
(b) four time
(c) half
(d) double
Fill in the following blank with suitable words:
Resistance is measured in .............. The resistance of a wire increases as the length ..............; as the temperature ..............; and as the cross-sectional area .............. .
State Ohm’s law and draw a neat labelled circuit diagram containing a battery, a key, a voltmeter, an ammeter, a rheostat and an unknown resistance to verify it.
Calculate the current flowing through a wire of resistance 5 Ω connected to a battery of potential difference 3 V.
A wire of resistance 9 ohm having length 30 cm is tripled on itself. What is its new resistance?
In the circuit shown below in Fig, calculate the value of x if the equivalent resistance between A and B is 4 Ω.
In the circuit shown in the figure, find the total resistance of the circuit and the current in the arm AD.
How does an increase in the temperature affect the specific resistance of a :
(i) Metal and
(ii) Semiconductor ?
Answer the following question.
Distinguish between Ohmic and non-ohmic substances; explain with the help of example.
SI unit of resistance is:
A wire connected to a power supply of 230 V has power dissipation P1. Suppose the wire is cut into two equal pieces and connected parallel to the same power supply. In this case, power dissipation is P2. The ratio of `"P"_2/"P"_1` is
Write a short note on superconductors?
Obtain the macroscopic form of Ohm’s law from its microscopic form and discuss its limitation.
Two conductors are made of the same material and have the same length. Conductor A is a solid wire of diameter 1 mm. Conductor B is a hollow tube of outer diameter 2 mm and inner diameter 1 mm. Find the ratio of resistance RA to RB.
State Ohm's Law. Represent it mathematically.
