Questions & Answers
521 answers across all subjects
Why do we get an electric shock?
We get an electric shock because the human body is a good conductor of electricity. When our body comes in contact with a source of electricity, current can pass through it. This flow of current interferes with the normal functioning of our nerves and muscles, which causes a shock. The severity of the shock depends on the amount of current, voltage, and duration of contact.
How does an electric cell produce electricity?
An electric cell produces electricity from the chemical energy stored inside it. Inside the cell, chemical reactions take place, which create a difference in electric potential between the two terminals. This potential difference causes electric charges to move, producing an electric current when the circuit is completed.
What are conductors?
Ans: Conductors are materials that allow electric current to pass through them easily. They have free electrons that move freely when electricity is applied. Metals are generally good conductors of electricity. Examples: Copper, aluminum, iron, etc.
An electric cell has how many terminals?
An electric cell has two terminals—a positive terminal (+) and a negative terminal (–). These terminals help in the flow of electric current through a circuit. The electric current flows from the positive terminal to the negative terminal through the external circuit.
What is a switch?
A switch is a simple electrical device that is used to either complete or break an electric circuit. When the switch is in the “ON” position, it allows electric current to flow through the circuit, and the device connected to it starts working. When it is in the “OFF” position, the circuit is broken, and the current stops flowing. Switches are commonly used in homes to control lights, fans, and other appliances.
How will you test the presence of proteins in food items?
The presence of proteins in food can be tested using a chemical test with nitric acid. First, take a small amount of crushed food in a test tube. Add a few drops of concentrated nitric acid and heat it slightly. If the food turns yellow, it indicates the presence of protein. When ammonium hydroxide is added, the colour changes from yellow to deep orange, confirming the presence of proteins.
What are vitamins?
Vitamins are complex organic substances required by the body in small amounts for proper growth and health. They do not provide energy but help regulate various body functions. Important vitamins required by our body include Vitamin A, B-complex, C, D, E, and K. These vitamins help maintain healthy skin, bones, eyes, blood, and immunity.
What are dietary fibres? Explain their importance.
Dietary fibres, also known as roughage, are components of plant foods that cannot be digested by the human body. Although roughage does not provide nutrients or energy, it is very important for proper digestion. It helps food move smoothly through the digestive system and prevents constipation. Foods rich in dietary fibres include whole grains, fruits, vegetables, pulses, and potatoes.
What are carbohydrates?
Carbohydrates are organic compounds made of carbon, hydrogen, and oxygen. They are mainly produced by plants during the process of photosynthesis. Common examples of carbohydrates include glucose, sugar, and starch. Carbohydrates are the main and cheapest source of energy for the body. Foods such as rice, wheat, potatoes, bread, and sugar are rich in carbohydrates.
Why is glucose called a source of instant energy?
Glucose is called a source of instant energy because it is directly absorbed into the bloodstream and quickly used by the body cells during respiration to release energy. Unlike other foods that need to be digested first, glucose can be used immediately by the body. That is why glucose drinks are often given to people who feel weak or tired.
Name two energy-giving components of food.
The two main energy-giving components of food are: Carbohydrates Fats Carbohydrates provide quick energy to perform daily activities, while fats store energy in the body and provide energy when required.
Name the disease caused by the deficiency of iodine. Suggest a few food items to cure it.
The disease caused by the deficiency of iodine is called goiter. In this disease, the thyroid gland in the neck becomes enlarged. To prevent or cure iodine deficiency, people should eat foods rich in iodine such as iodized salt, fish, seafood, milk, eggs, and seaweed. Using iodized salt in daily cooking is the easiest way to prevent goiter.
Name the protein present in the blood. What is the function of proteins in our body?
The protein present in blood is hemoglobin. Hemoglobin helps in carrying oxygen from the lungs to different parts of the body. Proteins are very important nutrients because they help in the growth and repair of body tissues. They are also needed for the formation of muscles, enzymes, hormones, and body cells. Foods rich in proteins include pulses, milk, eggs, meat, fish, and beans.
Name the disease caused by the deficiency of the following nutrients.
Iron: Anemia Vitamin A: Loss of vision or night blindness Vitamin B1: Beriberi Vitamin C: Scurvy Deficiency diseases occur when the body does not receive enough of certain nutrients over a long period of time.
Which components of food are known as protective foods?
Vitamins and minerals are known as protective foods. They help protect the body against diseases and keep the body functioning properly. Vitamins help maintain healthy skin, eyes, bones, and immunity. Minerals help in the formation of bones, teeth, and blood. For example, vitamin C helps prevent infections, while iron helps in the formation of blood. Protective foods are mainly obtained from fruits, vegetables, milk, eggs, and green leafy vegetables. Including these foods in our daily diet helps maintain good health and prevents deficiency diseases.
How will you test the starch in a food item?
The presence of starch in a food item can be tested using an iodine solution test. To perform the test, take a small quantity of the food item and place it on a plate or in a test tube. Then add 2–3 drops of dilute iodine solution to it. If the food item turns blue-black in colour, it indicates the presence of starch. This happens because iodine reacts with starch to produce a blue-black colour. Foods such as potatoes, rice, bread, and wheat usually give a positive test for starch.
Define Obesity.
Obesity is a condition in which excessive fat accumulates in the body. This usually happens when a person eats more food than the body needs, especially foods rich in fats and sugars. Eating too many fried foods, sweets, fast foods, ghee, butter, and oily snacks such as samosa, poori, and chips can lead to obesity. Lack of physical activity and exercise also contributes to this condition. Obesity can lead to several health problems such as heart disease, diabetes, high blood pressure, and joint pain. Therefore, it is important to maintain a balanced diet and perform regular physical exercise to keep the body healthy.
What is a balanced diet?
A balanced diet is a diet that contains all the essential nutrients in the correct proportions required by the body. These nutrients include carbohydrates, proteins, fats, vitamins, minerals, fibres, and water. A balanced diet also includes different types of food such as cereals, pulses, fruits, vegetables, milk, and fats. Each type of food provides specific nutrients that help the body grow, repair tissues, and protect against diseases. Eating a balanced diet helps maintain good health, proper growth, strong immunity, and sufficient energy to perform daily activities. Therefore, it is very important to include a variety of food items in our daily meals.
What are the major nutrients needed for the growth of our body?
Our body requires several nutrients for proper growth, development, and good health. The major nutrients present in food are carbohydrates, proteins, fats, vitamins, minerals, dietary fibres (roughage), and water. Each nutrient performs a specific function in the body. Carbohydrates are the main source of energy and help us perform daily activities. Proteins are needed for the growth and repair of body tissues and muscles. Fats also provide energy and help in keeping the body warm. Vitamins and minerals protect the body from diseases and help in the proper functioning of organs. Dietary fibres help in digestion and removal of waste from the body, while water helps in transporting nutrients, regulating body temperature, and removing waste products. All these nutrients must be consumed in the right quantities for maintaining good health.
How are jute fibres obtained?
Jute fibres are obtained from the stem of the jute plant. The process of obtaining jute fibres involves several steps. First, the jute plants are harvested when they are fully grown. Then the stems of the plants are tied into bundles and immersed in water for several days. This process is known as retting, during which microorganisms help in rotting the stems and loosening the fibres. After retting, the fibres are separated from the stem by hand. The extracted fibres are then washed, dried, and processed further. These fibres are later spun into yarn and used to make various products such as ropes, sacks, carpets, and bags.