Light – Reflection and Refraction — Science STD 10 — Question

What is yeast? Describe the process of reproduction in yeast with the help of labelled diagrams.

Lithium, sodium and potassium are all metals that react with water to liberate hydrogen gas. Is there any similarity in the atoms of these elements? Explain your answer.

What is the function of insulin hormone? What type of patients are given insulin injections?

What is a group in the periodic table? In which part of a group would you separately expect the elements to have.

1. The greatest metallic character.
2. The largest atomic size?

Explain the formation of scum when hard water is treated with soap.

1. What is observed when a solution of potassium iodide is added to a solution of lead nitrate taken in a test tube?
2. What type of reaction is this?
3. Write a balanced chemical equation to represent the above reaction.

Study the food chain given below and answer the questions that follow :

(a) If the amount of energy available at the third trophic level is 100 joules, then how much energy will be available at the producer level? Justify your answer.
(b) Is it possible to have 2 more trophic levels in this food chain just before the fourth trophic level? Justify your answer.

What causes joining up of stock and scion in grafting? Name one positive trait that the plant contributing scion should have and one positive trait that the plant contributing the stock should have.

What is puberty? Who attains puberty at an earlier age in human beings: male or female (boy or girl)?

Describe two anomalies of Mendeleev’s periodic classification of elements.