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Anannya responded to the question: Why do electrical appliances with metallic bodies are connected to the mains through a three pin plug, whereas an electric bulb can be connected with a two pin plug? She wrote: Three pin connections reduce heating of connecting wires. (i) Is her answer correct or incorrect? Justify. (ii) What is the function of a fuse in a domestic circuit?
(i) Anannya’s answer is incorrect. Three-pin plugs are used to connect electrical appliances having metallic bodies to the earth wire, which provides a low-resistance path for leakage current and prevents electric shock. It does not reduce heating of wires. (ii) A fuse acts as a safety device in domRead more
(i) Anannya’s answer is incorrect. Three-pin plugs are used to connect electrical appliances having metallic bodies to the earth wire, which provides a low-resistance path for leakage current and prevents electric shock. It does not reduce heating of wires.
See less(ii) A fuse acts as a safety device in domestic circuits. It contains a thin wire that melts and breaks the circuit when the current exceeds the safe limit, thus protecting the wiring and appliances from short circuits and overloads.
List the factors on which the resistance of a conductor depends.
The resistance of a conductor is influenced by several factors. It increases with the length of the conductor and decreases with the area of cross-section. It also depends on the nature of the material—metals like copper and aluminium have low resistance, while alloys like nichrome have high resistaRead more
The resistance of a conductor is influenced by several factors. It increases with the length of the conductor and decreases with the area of cross-section. It also depends on the nature of the material—metals like copper and aluminium have low resistance, while alloys like nichrome have high resistance. Temperature also affects resistance; in most metals, resistance increases with rise in temperature. Thus, resistance (R) can be expressed as R = ρ(l/A), where ρ is the resistivity of the material.
See lessState the law that explains the heating effect of current with respect to the measurable properties in an electrical circuit.
According to Joule’s Law of Heating, the heat produced in an electrical circuit depends on measurable quantities—current (I), resistance (R), and time (t). The law states that the heat generated (H) in a conductor is directly proportional to the square of current, resistance of the conductor, and tiRead more
According to Joule’s Law of Heating, the heat produced in an electrical circuit depends on measurable quantities—current (I), resistance (R), and time (t). The law states that the heat generated (H) in a conductor is directly proportional to the square of current, resistance of the conductor, and time for which current passes, represented by H = I²Rt. This explains why thicker wires produce less heat and why excessive current can cause heating or damage in electrical appliances.
See lessWhat is the probability of a girl or a boy being born in a family? Justify your answer.
There are 50% chances that a girl may be born and 50% chances that a boy may be born. It can be explained as follows: Most human chromosomes have a maternal copy and a paternal copy. We have 22 such chromosomes. One pair of chromosomes called sex chromosomes is odd in not always being a perfect pairRead more
There are 50% chances that a girl may be born and 50% chances that a boy may be born. It can be explained as follows:
Most human chromosomes have a maternal copy and a paternal copy. We have 22 such chromosomes. One pair of chromosomes called sex chromosomes is odd in not always being a perfect pair. Women have a perfect pair of sex chromosomes, both called X. (XX)
But men have a mismatched pair of sex chromosomes in which one is normal sized – X chromosome while the other is a short one called Y chromosome. (XY)
A child receives one chromosome from mother which is essentially X chromosome. A child who inherits an X chromosome from her father will be a girl, and one who inherits a Y chromosome from him will be a boy.
See lessWe are advised to take iodised salt in our diet by doctors. Justify it’s importance in our body.
Doctors recommend consuming iodised salt because iodine is a vital micronutrient required for the synthesis of thyroid hormones—thyroxine and triiodothyronine. These hormones control metabolism, body temperature, and overall growth. Iodine also supports brain development and nervous system functionsRead more
Doctors recommend consuming iodised salt because iodine is a vital micronutrient required for the synthesis of thyroid hormones—thyroxine and triiodothyronine. These hormones control metabolism, body temperature, and overall growth. Iodine also supports brain development and nervous system functions. A deficiency of iodine leads to goitre, fatigue, and mental dullness. Regular intake of iodised salt prevents such disorders and helps maintain a healthy thyroid gland, ensuring the body’s proper growth, development, and energy balance.
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