Introduction

Q.

Why does the life exist on earth?Write 3 conditions

Q.

The filament of a bulb glows due to?

1. Heating effect of the electric current.

2. Magnetic effect of electric current.

3. Chemical effect of electric current.

4. All of these.

Q. A positive charge q exerts a force of magnitude - 0.2 N on another charge, which has a magnitude twice as the other charge. Find the magnitude of each charge if the distance separating them is equal to 50 cm. (Ans = 1.66 × 10-6 C)

Q. Why small gaps are left between concrete roads?

Q.

What are the various environmental conditions available on Earth which are responsible for the existence and continuation of life on Earth?

Q.

What is the SI unit of luminous intensity?

1. henry

2. candela

3. ampere

4. watt

Q. If a force is applied on an object in the opposite direction of its motion, speed of the object ______.

1. decreases
2. increases
3. doesn’t change
4. First increases, then decreases

Q. Spike in football shoes helps in _______.

1. sliding
2. increasing adhesion
3. decreasing adhesion
4. better interlocking

Q. In a circuit tester, LED bulb is used in place of a normal bulb because LED bulbs needs ______ electric current.

1. alternate

2. less

3. equivalent

4. more

Q. In gold plating, the electrode connected to the positive terminal of the battery must be made of gold.

1. True
2. False

Q. If a force is applied on an object in the opposite direction of its motion, speed of the object ______.

1. decreases
2. increases
3. doesn’t change
4. First increases, then decreases

Q. Would the bulb glow in the circuit shown in figure?

Q. According to conservation of energy, heat gained by one body is equal to heat lost by another body.

1. False
2. True

Q. In the given figure, the bulb connected to the circuit does not glows. What might be the possible reason for this, assuming circuit connections are done properly?

1. The current through the circuit is too less for the bulb's filament to be heated and glowed adequately.
2. The current is too high in the circuit to magnetize the bulb.
3. The current through the circuit is too weak for the chemical reaction required for the bulb to glow.
4. (a) and (b) above.

Q. An electrode is made of a substance which is a bad conductor of electricity.

1. False
2. True

Q. Which of the following liquids has lowest boiling point?

1. Water
2. Ether
3. Milk
4. Alcohol

Q. The graph above shows the amount of water remaining in a tank each time a pail was used to remove $x$ gallons of water. If $5$ gallons were in the tank originally and $2\frac{1}{2}$ gallons remained after the last pail containing $x$ gallons was removed, what is the value of $x$ ?

1. $\frac{1}{3}$
2. $\frac{1}{4}$
3. $\frac{1}{2}$
4. $\frac{1}{5}$

Q.

Gaia hypothesis states that:
"Living systems act as environmental regulators ensuring chemical levels stay within limits congenial to Gaia's health."
What does "environmental regulators" stand here for?

1. Temperature

2. Oxygen

3. Water

4. Technology

Q. What is the net force and its direction on the block given below?

1. 10 N (North)
2. 20 N (North)
3. 8 N (East)
4. 16 N (East)

Q. An electric bulb only glows when the circuit is closed.

1. False
2. True