Premium Online Home Tutors

3 Tutor System

Starting just at 265/hour

Which of the following terms does not represent electrical power in a circuit?

- (a)\( I^2R \)
- (b) \( IR^2 \)
- (c)VI
- (d) \(V^2 \)/R

Answer :

**(b)**\( IR^2 \)

Power of an appliance determines the rate at which electrical energy is delivered to it.
Electrical power is given by the expression, P = VI … (i)
According to Ohm's law, V = IR … (ii)
where,
V = Potential difference
I = Current
R = Resistance
So, it can be written that

- A piece of wire of resistance R is cut into five equal parts. These parts are then connected in parallel. If the equivalent resistance of this combination is R', then the ratio R/R' is - (a) \(\frac{1}{25} \) (b) \(\frac{1}{5} \) (c) 5 (d) 25
- An electric bulb is rated 220 V and 100 W. When it is operated on 110 V, the power consumed will be - (a) 100W (b) 75W (c)50W (d) 25W
- Two conducting wires of the same material and of equal lengths and equal diameters are first connected in series and then parallel in a circuit across the same potential difference. The ratio of heat produced in series and parallel combinations would be - (a) 1:2 (b) 2:1 (c)1:4 (d) 4:1
- How is a voltmeter connected in the circuit to measure the potential difference between two points ?
- A copper wire has diameter 0.5 mm and resistivity of \( 1.6 × 10^-8 \Omega m. \) What will be the length of this wire to make its resistance 10 \(\Omega \)? How much does the resistance change if the diameter is doubled?
- The values of current I flowing in a given resistor for the corresponding values of potential difference V across the resistor are given below ? V(volts) 1.6 3.4 6.7 10.7 13.2 A(amperes) 0.5 1.0 2.0 3.0 4.0 Plot a graph between V and I and calculate the resistance of that resistor.
- 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 battery of 9 V is connected in series with resistors of 0.2 \(\Omega \) , 0.3 \(\Omega \), 0.4 \(\Omega \), 0.5 \(\Omega \) and 12 \(\Omega \), respectively. How much current would flow through the 12 \(\Omega \) resistor?
- How many 176 \(\Omega \) resistors (in parallel) are required to carry 5 A on a 220 V line?
- Show how you would connect three resistors, each of resistance 6 \(\Omega \), so that the combination has a resistance of (i) 9 \(\Omega \), (ii) 4 \(\Omega \).
- Several electric bulbs designed to be used on a 220 V electric supply line, are rated 10 W. How many lamps can be connected in parallel with each other across the two wires of 220 V line if the maximum allowable current is 5 A?
- A hot plate of an electric oven connected to a 220 V line has two resistance coils A and B, each of 24 \(\Omega \)resistances, which may be used separately, in series, or in parallel. What are the currents in the three cases?
- Compare the power used in the 2 R resistor in each of the following circuits: (i) a 6 V battery in series with 1 R and 2 R resistors, and (ii) a 4 V battery in parallel with 12 R and 2 R resistors.
- Two lamps, one rated 100 W at 220 V, and the other 60 W at 220 V, are connected in parallel to electric mains supply. What current is drawn from the line if the supply voltage is 220 V?
- Which uses more energy, a 250 W TV set in 1 hr, or a 1200 W toaster in 10 minutes?
- An electric heater of resistance 8\(\Omega \) draws 15 A from the service mains 2 hours. Calculate the rate at which heat is developed in the heater.
- Explain the following Why is the tungsten used almost exclusively for filament of electric lamps? Why are the conductors of electric heating devices, such as bread-toasters and electric irons, made of an alloy rather than a pure metal? Why is the series arrangement not used for domestic circuits? How does the resistance of a wire vary with its area of cross-section? Why are copper and aluminium wires usually employed for electricity transmission?
- 21. An electric iron of resistance 20Ω takes a current of 5 A. Calculate the heat developed in 30 s.

- NCERT solutions for class 10 maths chapter 1 Real Numbers
- NCERT solutions for class 10 maths chapter 1 Electricity, Light , Carbon and it's compounds
- NCERT solutions for class 10 maths chapter 2 Polynomials
- NCERT solutions for class 10 maths chapter 3 Pair of linear equations in two variables
- NCERT solutions for class 10 maths chapter 4 Quadratic Equations
- NCERT solutions for class 10 maths chapter 5 Arithmetic Progressions
- NCERT solutions for class 10 maths chapter 6 Triangles
- NCERT solutions for class 10 maths chapter 7 Coordinate Geometry
- NCERT solutions for class 10 maths chapter 8 Introduction to Trigonometry
- NCERT solutions for class 10 maths chapter 9 Some Applications of Trigonometry
- NCERT solutions for class 10 maths chapter 10 Circles
- NCERT solutions for class 10 maths chapter 11 Constructions
- NCERT solutions for class 10 maths chapter 12 Areas related to circles
- NCERT solutions for class 10 maths chapter 13 Surface Areas and Volumes
- NCERT solutions for class 10 maths chapter 14 Statistics
- NCERT solutions for class 10 maths chapter 15 Probability

- NCERT solutions for class 10 science chapter 1 Chemical Reactions and Equations
- NCERT solutions for class 10 science chapter 2 Acids, Bases and Salts
- NCERT solutions for class 10 science chapter 3 Metals and Non Metals
- NCERT solutions for class 10 science chapter 4 Carbon and its Compounds
- NCERT solutions for class 10 science chapter 5 Periodic Classification of Elements
- NCERT solutions for class 10 science chapter 6 Life Processes
- NCERT solutions for class 10 science chapter 7 Control and Coordination
- NCERT solutions for class 10 science chapter 8 How do Organisms Reproduce
- NCERT solutions for class 10 science chapter 9 Heredity and Evolution
- NCERT solutions for class 10 science chapter 10 Light Reflection and Refraction
- NCERT solutions for class 10 science chapter 11 Human Eye and Colorful World
- NCERT solutions for class 10 science chapter 12 Electricity
- NCERT solutions for class 10 science chapter 13 Magnetic Effect of Electric Current
- NCERT solutions for class 10 science chapter 14 Sources of Energy
- NCERT solutions for class 10 science chapter 15 Our Environment
- NCERT solutions for class 10 science chapter 16 Management of Natural Resources