1. (a) When a ray travels from A (refractive index 1.6) to B (1.8), it moves from a rarer to a denser medium. In this case, the speed of light decreases, causing the ray to bend towards the normal. Therefore, the bending towards the normal occurs only in the transition from medium A to medium B. (b) WhRead more

    (a) When a ray travels from A (refractive index 1.6) to B (1.8), it moves from a rarer to a denser medium. In this case, the speed of light decreases, causing the ray to bend towards the normal. Therefore, the bending towards the normal occurs only in the transition from medium A to medium B.

    (b) When the ray moves from B (refractive index 1.8) to C (1.5), it passes from a denser to a rarer medium. Light travels faster in a medium with lower refractive index. Thus, in medium C, with refractive index 1.5, the speed of light increases compared to medium B, because of the inverse relationship between refractive index and velocity.

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  2. ANSWER: (A) Electrolytic decomposition of water/electrolysis of water. (B) The gas collected at cathode is hydrogen which is double the volume of oxygen collected at anode. (C) 2H2O (l) + Electric current → 2H2 (g) + O2 (g) When an electric current is passed through water, it undergoes electrolysis.Read more

    ANSWER:

    (A) Electrolytic decomposition of water/electrolysis of water.

    (B) The gas collected at cathode is hydrogen which is double the volume of oxygen collected at anode.

    (C) 2H2O (l) + Electric current → 2H2 (g) + O2 (g) When an electric current is passed through water, it undergoes electrolysis. Two molecules of liquid water (2H₂O) decompose to form hydrogen gas (2H₂) and oxygen gas (O₂). Hydrogen collects at the cathode, while oxygen collects at the anode.

    (D) Water is not a good conductor of electricity sulphuric acid is added in the water to make, it a good conductor of electricity.

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  3. ANSWER: [C] Explanation: When an acid reacts with a metal, hydrogen gas is liberated. In the given reaction, when dilute sulphuric acid reacts with zinc granules, hydrogen gas is liberated and zinc sulphate solution is formed: Zn(s) + H₂SO₄(aq) → ZnSO₄(aq) + H₂ (g) The presence of hydrogen gas is teRead more

    ANSWER: [C]

    Explanation: When an acid reacts with a metal, hydrogen gas is liberated. In the given reaction, when dilute sulphuric acid reacts with zinc granules, hydrogen gas is liberated and zinc sulphate solution is formed:

    Zn(s) + H₂SO₄(aq) → ZnSO₄(aq) + H₂ (g)

    The presence of hydrogen gas is tested by bringing a lighted candle near it. When a lighted candle is brought near the test tube containing hydrogen gas, it burns with a “pop sound” making a little explosion. Hence, acid “X” is sulphuric acid and gas “Y” is hydrogen gas.

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  4. (i) Fertilization in human females takes place in the fallopian tube (oviduct). (ii) The inner lining of the uterus, called the endometrium, becomes thick, soft, and richly supplied with blood vessels each month. This provides a warm, nutrient-rich environment to receive the fertilized egg and suppoRead more

    (i) Fertilization in human females takes place in the fallopian tube (oviduct).

    (ii) The inner lining of the uterus, called the endometrium, becomes thick, soft, and richly supplied with blood vessels each month. This provides a warm, nutrient-rich environment to receive the fertilized egg and support the growing embryo.

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  5. The developing embryo gets nutrition from the mother’s blood through a special tissue called the placenta. The placenta forms a connection between the embryo and the mother’s uterus. Tiny finger-like structures, called villi, grow into the uterine tissue, increasing the surface area for exchange. ThRead more

    The developing embryo gets nutrition from the mother’s blood through a special tissue called the placenta. The placenta forms a connection between the embryo and the mother’s uterus. Tiny finger-like structures, called villi, grow into the uterine tissue, increasing the surface area for exchange. The mother’s blood vessels surround these villi and supply oxygen, glucose, amino acids, and other nutrients, which diffuse into the embryo’s blood. At the same time, waste products from the embryo pass into the mother’s blood for removal.

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