Q:
Explain the following.
(a) Why is the tungsten used almost exclusively for filament of electric lamps?
(b) Why are the conductors of electric heating devices, such as bread-toasters and electric irons, made of an alloy rather than a pure metal?
(c) Why is the series arrangement not used for domestic circuits?
(d) How does the resistance of a wire vary with its area of cross-section?
(e) Why are copper and aluminium wires usually employed for electricity transmission?
A:
(a) Due to high melting point and high resistivity of tungsten, it does not burn at a high temperature. As the electric lamps glow at very high temperatures hence, the tungsten is used as heating element of electric bulbs.
(b) Bread toasters and electric irons are made of alloy because resistivity of an alloy is more than that of pure metals. Due to high resistivity, they produce large amount of heat.
(c) In a series circuit, there is a voltage distribution. Each element of a series circuit receives a small voltage for a large supply voltage. Thus, the amount of current decreases and the device becomes hot. Therefore, series arrangement is not used in domestic circuits.
(d) Resistance (R) of a wire is inversely proportional to its area of cross-section (A).
(e) The wires made of copper or aluminium have low resistivity and they are good conductors of electricity. Therefore, they are frequently used for electricity transmission.
Q:
An electric heater of resistance 8 Ω draws 15 A from the service mains 2 hours. Calculate the rate at which heat is developed in the heater.
A:
Q:
Which uses more energy, a 250 W TV set in 1 hr, or a 1200 W toaster in 10 minutes?
A:
Q:
Two lamps, one rated 100 W and 220 V, and the other 60 W at 220 W, are connected in parallel to electric mains supply. What current is drawn from the line if the supply voltage is 220 V?
A:
Q:
Compare the power used in the 2 Ω in each of the following circuits:
(i) a 6 V battery in series with 1 Ω and 2 Ω resistors, and
(ii) a 4 V battery in parallel with 12 Ω and 2 Ω resistors.
A:
Q:
A hot plate of an electric oven connected to a 220 V line has two resistance coils A and B, each of 24 resistances which may be used separately, in series or in parallel. What are the currents in the three cases?
A:
Q:
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:
Q:
Show how would you connect three resistors, each of resistance 6 Ω, so that the combination has a resistance of (i) 9 Ω (ii) 4 Ω.
A:
Q:
How many 176 resistors (in parallel) are required to carry 5 A on a 220 V line?
A:
Q:
A battery of 9 V is connected in series with resistors of 0.2 Ω, 0.3 Ω, 0.4 Ω, 0.5 Ω and 12 Ω, respectively. How much current would flow through the 12 resistors?
A:
Q:
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:
Q:
The value of current (I) flowing in a given resistor for the corresponding values of potential difference (V) across the resistor are given below-
| I (amperes) | 0.5 | 1.0 | 2.0 | 3.0 | 4.0 |
| V (volts) | 1.6 | 3.4 | 6.7 | 10.2 | 13.2 |
Plot a graph between V and I and calculate the resistance of that resistor.
A:
Q:
A copper wire has diameter 0.5 mm and resistivity of 1.6 × 10−8 Ωm. What will be the length of this wire to make its resistance 10 Ω? How much does the resistance change if the diameter is doubled?
A:
Q:
How is a voltmeter connected in the circuit to measure the potential difference between two points?
A:
A voltmeter need to be connected in parallel in a circuit to measure the potential difference between two points.
Q:
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
A:
Q:
An electric bulb is rated 220 V and 100 W. When it is operated on 110 V, the power consumed will be
(a) 100 W
(b) 75 W
(c) 50 W
(d) 25 W
A:
Q:
A:
Q:
A:
Benefits of NCERT Solutions
1. It helps students practice loads of questions from every chapter which encourages them to make their concepts more grounded..
2. NCERT Solutions for Class 10 encourages you to upgrade your knowledge and clear your concepts with the goal that you can score well in your exams.
3. These solutions are the best examination materials to know your weak and strong points. It is essential to work on your weak points to score well in the exams.
4. Most of the questions in exams are asked in a similar arrangement from NCERT textbooks. Hence, students should altogether revise every chapter’s solution to get a good command in subjects
Tips & Strategies for Class 10 Exam Preparation
2. Refer to NCERT Solutions given on the Extramarks website to clear your concepts anytime while preparing for your exams.
3. Start studying with the help of Extramarks – The Learning App to pass your exams with flying colours. It provides complete study material with solved and unsolved papers.
4. It is important to clear all your doubts before the exam with your teachers or Alex (an AI studybot).
5. While reading or learning a chapter, make sure to make notes with algorithms, formulas, theorems, etc., and study them for a quick revision before exams.
6. Practice an ample number of question papers to make your concepts stronger.
7. Take rest and a proper meal. Don’t stress too much.
Why opt for Extramarks NCERT Solutions for Class 10 ?
NCERT 10 solutions for math are in-depth solutions written in very basic and simple language which makes them easy to understand. It gives sufficient study material to practice with to the students which the latter can use for practicing for board exams. Extramarks website has NCERT solutions for all classes that can be used by students of different classes. These solutions can be accessed by visiting the footer section of the website. Prepare notes and learn from NCERT solutions, go through them thoroughly before the exam, and practice with the questions that crop up in NCERT solutions.
Yes, Extramarks website has NCERT solutions for class 10 along with all other classes of CBSE listed on the footer section. These solutions have been prepared by top faculty members who have years of experience and expertise in teaching CBSE students.
Extramarks class 10 NCERT solutions are crucial for board preparation for students. These solutions are given in a simple language which makes it easy to understand for all and it proves to be the basis for board examination which further helps the students in understanding the extensive study material. Class 10 NCERT solutions focus on fundamental clarity of the concepts which further helping in clearing all doubts and helping students achieve concept clarity. NCERT solutions provide enough practice and study material to students that they can use to test their knowledge
Yes, class 10 solutions (NCERT) are sufficient to prepare for class 10 board exams. NCERT solutions are simple and easy to understand written in a way that is appealing to students. NCERT solutions form the basis of examination of class 10 board so they prove to be a sufficient solution which also gives enough study material to practice with to students. Different types of NCERT solutions help students prepare for the exam through varied formats and provide them concept clarity.
Class 10 CBSE NCERT solutions are sufficient to prepare for board exams but if you want to test your knowledge and would like to browse more solutions then you can use textbook solutions to prepare for the exam. Although the NCERT solutions are enough for preparing for the exam, you can check out the solved and unsolved sample papers along with textbook solutions from Extramarks - The Learning App and website
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