The gravitational constant (G) is a fundamental physical constant that appears in Newton's law of universal gravitation. It determines the strength of the gravitational force between two objects, and it is always the same, regardless of the distance between the objects or their masses. The value of G is approximately 6.674 x 10⁻¹¹ N(m/kg)².
Chapter: Chemical Effects of Current
Directions: Read the following and answer the questions given below:
Case Study
Take out carbon rods carefully from two discarded cells. Clean their metal caps with sandpaper. Wrap copper wires around the metal caps of the carton rods to form electrodes and join them to a battery, Pour a cupful of water into a glass/plastic bowl. Add a teaspoonful of salt or a few drops of lemon juice to water to make it more conducting. Now immerse the electrodes in this solution. Make sure that the metal caps of the carbon rods are outside the water. Wait for 3-4 minutes, Observe the electrodes carefully.
CBSE Class 8 - Physics - Sound - Case Study Based Question
Q1. Read the following and answer the questions given below:
Sound is a form of energy that is produced when air molecules vibrate in a particular pattern called waves. Hence, the sound is a wave. Sound is produced by vibrating objects. Vibration can be described as to and fro motion of an objects. Sound cannot be produced without any vibrations. Sound always requires a medium to travel from the source of its production to the receiver end. Speed of the sound is maximum in solids and minimum in gases.
Very Short Answer Type Questions
1. Name three useful products of coal.
2. Which product of coal is used as a reducing agent in the extraction of metals?
3. Name the process by which plant material (or vegetation) buried deep under the earth was slowly converted into coal.
4. Name the product of coal, which is a thick black liquid with an unpleasant smell.
Various steps involved in agriculture are collectively known as agricultural practices, which include:
1. At present about 118 elements are known.
2. Elements can be divided into two main groups: metals and non-metals.
3. Elements which form positive ions by losing electrons are called metals. Thus, metals are the elements which have the tendency to lose electrons.
