P-1 Metallurgy — Science STD 10 — Question

Draw a labelled diagram of the human digestive system. With the help of this diagram, describe the process of digestion of food in man (humans).

Write Short note: Seed germination.

Taking into consideration the period of the elements given below, answer the following questions:

Element	Atomic radius (pm)
O	66
B	88
C	77
N	74
Be	111
Li	152

i. Arrange the above elements in a decreasing order of their atomic radii.
ii. State the period to which the above elements belong.
iii. Why this arrangement of elements is similar to the above period of the modern periodic table?
iv. Which of the above elements have the biggest and the smallest atom?
v. What is the periodic trend observed in the variation of atomic radius while going from left to right within a period?

An electric circuit consisting of a 0.5m long nichrome wire XY, an ammeter, a voltmeter, four cells of 1.5V each and a plug key was set up.

1. Draw a diagram of this electric circuit to study the relation between the potential difference maintained between the points ‘X’ and ‘Y’ and the electric current flowing through XY.
2. Following graph was plotted between V and I values:

What would be the values of ratios when the potential difference is 0.8V, 1.2V and 1.6V respectively? What conclusion do you draw from these values?

3. What is the resistance of the wire?

When the solution of substance X is added to a solution of potassium iodide, then a yellow solid separates out from the solution:

1. What do you think substance X is likely to be?
2. Name the substance which the yellow solid consists of.
3. Which characteristic of chemical reaction is illustrated by this example?
4. Write a balanced chemical equation for the reaction which takes place. Mention the physical states of all the reactant and products involved in the chemical equation.

The image in a plane mirror is virtual and laterally inverted. What does this statement mean?

Give scientific Reason :
Inert gases exist in the form of free atoms.

An object is placed 10cm from a lens of focal length 5cm. Draw the ray diagrams to show the formation of image if the lens is:

1. Converging, and
2. Diverging.

How much energy will be available to hawks in the food chain comprising hawk, snake, paddy and mice, if 10,000 J of energy is available to paddy from the sun?