Q. Define solar luminosity.

Q. Why ethyl mercaptan is added to liquid petroleum gas?

Q. The wavelength of electromagnetic radiations $A$, $B$ and $C$ are given below :

Electromagnetic radiation	Wavelength
$A$	$4\times {10}^{-9}m$
$B$	$0.1\times {10}^{-9}m$
$C$	$10\times {10}^{-9}m$

Which of the above electromagnetic radiations causes photoelectric effect in most number of metals? Give scientific reason for this.

Q. List the uses of detergents.

Q. Draw the diagram of Permutit column used in softening hard water and label the part:

Q. A body $A$ is moving in a straight line with a constant speed of $10{ms}^{-1}$. Another body $B$ having same mass as that of $A$ is moving in a circular path with a constant speed of $10{ms}^{-1}$. The correct statement related to their acceleration is

1. The acceleration of body $A$ is more than the acceleration of body $B$
2. The acceleration of body $B$ is zero
3. Only $B$ has acceleration
4. The acceleration of both $A$ and $B$ are same

Q. Match the components of nuclear power reactor given in Column-A with their functions given in Column-B. Write the correct answer in the space provided :

Q. In a group of hydrocarbons, the ratio between the carbon and hydrogen atoms is $1:2$. These hydrocarbons belong to which class?

1. Alkanes
2. Alkenes
3. Alkynes
4. Aromatic hydrocarbons

Q. Define centripetal force.

Q. A radioactive element $Y$ emits an alpha particle and a beta particle successively and changes into an element ${}_{82}{X}^{206}$. Find the atomic mass and atomic number of radioactive element $Y$.

Q. Which of the following measured do you take to conserve water?

1. Washing utensils in a pond
2. Using detergents to wash clothes
3. Disposing idols painted with artificial colours in a pond
4. Using water after washing vegetables for plants

Q. The device that uses solar energy in the form of heat is

1. Solar light
2. Solar panel used in artificial satellites
3. Solar cell
4. Solar cooker

Q. The silicon compound used in calico printing is:

1. quartz
2. silicon carbide
3. sodium silicate
4. silica

Q. Write down an application of Radiocarbon?

Q. Four metals $P$, $Q$, $R$ and $S$ react with water as given below:
I. $P$ reacts with cold water
II. $Q$ reacts with hot water
III. $R$ reacts with steam
IV. Red hot $S$ reacts with steam.
Then, highly reactive metal is:

1. $P$
2. $Q$
3. $R$
4. $S$

Q. Draw the diagram of a DC motor and label the parts.

Q. Write the balanced chemical equation when zinc reacts with dilute nitric acid.

Q. State Faraday's laws of electromagnetic induction.

Q. Imagine a planet $M$ having mass same as the earth and having radius $3$ times that of the earth.
a) Calculate the ratio of acceleration due to gravity on the surface of the planet $M$ to the acceleration due to gravity on the surface of the earth.
b) If the average value of acceleration due to gravity on the surface of the earth is $9.8{ms}^{-2}$, then find the value of average acceleration due to gravity on the surface of planet $M$.

Q. Draw the circuit symbol of $n-p-n$ transistor.

Q. In which of the following cases a listener experiences Doppler effect?

1. The listener is moving towards the source of sound
2. The listener and source of sound are moving with same velocity
3. The listener and the source of sound are stationary
4. None of the above

Q. The basic source of wind energy is __________.

Q. What are geostationary satellites? Write any one use of them.

Q. The different stages of preparing amorphous silicon are given below.
I. Silica is finely powdered.
II. The product is washed with hydrochloric acid.
III. The mixture of powdered silica and magnesium is heated in a fire-clay crucible.
IV. The product is washed with hydrofluoric acid to remove unchanged silica.
The correct arrangement of the above stages is :

1. I, III, II and IV
2. I, II, III and IV
3. IV, I, II and III
4. I, IV, III and II

Q. Which of the following is the best measure to save energy?

1. Four colleagues residing in the same colony travel to the office together by the same car
2. Each individual uses his own vehicle
3. Using vehicles to travel small distances
4. Keeping the vehicle engine 'on' during traffic jam

Q. In a radio receiver, the device that separates AF signals from RF signals is ___________.

Q. Draw the diagram of a single stage rocket and label the parts.

Q. The dopant to be added to make silicon an $n$-type of semiconductor is

1. Gallium
2. Antimony
3. Indium
4. Boron

Q. The device used to measure the distance and direction of underwater substances using ultrasonic waves is _____________.

Q. Draw the diagram of a Helium-Neon laser tube and label the parts.