Explore topic-wise InterviewSolutions in .

The materials that do not allow current to pass through them are called bad conductors of electricity

Correct option is  B) Electroplating

1. The wires are not properly connected so the circuit may be open. 

2. The liquid taken in the vessel may be a bad conductor of electricity which does not allowing the passage of current.

Hibiscus plant propagate by means of stem cuttings.

Some materials allow electric current pass through them easily. They are called good conductors of electricity.

Correct option is C) Motion of charge

1. Why does the bulb glow? 

2. How does the dry cell charged? 

3. Which energy is useful in charging the discharged dry cell? 

4. Shall we use that energy to get rid from electrical power cut?

There are two types of charges: Positive charge and negative charge. Like charges repel each other and unlike charges attract each other.

1. stem 

2. Stamens d r Androecium 

3. Ovary

LEDs glow even with a very small current passing through them. So they are used as indicators in electrical appliances like mobile phones, televisions, transformers, etc. to indicate whether the device is working or not.

Uses of electroplating:

1. Metals like iron are coated with deposits of nickel or chromium to prevent rusting. 

2. Machinery parts are often chromium plated to protect them from corrosion and at the same time to give them good polish. 

3. Electroplating is also used in repairing worn out parts of machinery. 

4. Electroplating is also done for ornamentation and decoration purposes. 

5. Processed food items are preserved in tin coated iron cans by electroplating method. 

6. Zinc coated iron by electroplating method is used for bridges and in automobiles.

No. Plastic cannot be coated on a metal by using electroplating. The reason is plastic being a carbon polymer does not dissociate into ions. So it does not allow passage of current. So it does not act as an electrolyte. So electrolysis process is not possible with plastic which is main criteria for electroplating. So plastic cannot be coated on a metal by the process of electroplating.

D) Chemical energy is converted into

Fire men use water to put out fire. Water containing dissolved salts is a good conduc¬tor of electricity. If fire men pour water on fire the electrical appliances near the fire may be wet if anybody touches those appliances they may have electric shock. In order to avoid people to get electric shock due to wet electrical appliances the fire men shut off electrical supply before they use water

The Liquids that conduct electricity will cause the magnetic needle to deflect because the electric current is capable of producing magnetic effect. The liquids like lemon juice, salt water and vegetable oil allow electricity to pass through them. Hence, these liquids can be used as in the beaker to show the given effect.

Water may conduct electricity. If the electrical supply for the area is not shut off and water is poured over electrical appliances, the electricity may pass through water and harm the firemen. That is why, in case of a fire, the firemen shut off the main electrical supply for the area before they use the water hoses. 

The advantage of using LEDs is because, they glow up even if very small amount of current passes through them.

Because wet hands have water and water is a good conductor of electricity. A person can get electric shock if he touches any electrical appliances with wet hands.

Here, L = 10 m;

ρ = 1.5 x 10³ kg^-3

Y = 6 x 10⁶ g f cm^-2

= 6 x 10⁶ x 980 dyne cm^-2

= 5.88 x 10⁸ Nm^-2

Let 'a' be the area of cross-section of the Indian rubber cord. Then,

F = weight of the rubber cord

= L x a x ρ x g

The weight of the rubber cord acts at its centre of gravity and hence the weight of the rubber cord will produce extension in the length L/2 of the cord.

Now, Y = {F(L/2)}/al

l = {F x L}/{2a x Y} = {L x a x ρ x g x L}/{2a x Y}

= {L²ρg}/{2Y} = {10² x 1.5 x 10³ x 9.8}/{2 x 5.88 x 10⁸}

= 1.25 x 10^-3 m = 1.25 mm

It is a sphere drawn around a particular molecule as centre and molecular range as radius.

It is the maximum distance upto which a molecule can exert force of attraction on another molecule. It is of the order of 10^-9 m for solids and liquids.

Correct Answer is: (c) π/2√R/g

The time period of oscillation of a particle undergoing SHM in the tunnel, starting from rest at the surface = 2π√R/g. The journey from the surface to the centre is one-fourth of an oscillation.

When a liquid is heated at constant pressure to its boiling point or when the pressure is reduced at a constant temperature it will convert to a gas. This process of a liquid changing to a gas is called evaporation.

One is the absorptive power of a perfectly black body.

In conduction and radiation.

Evaporation is used to separate solids dissolved in liquids, mainly water. It is used on a large scale to obtain common salt from sea water. Sea water is left in the open in large containers on sunny days. After a few days salt remains as residue and water evaporates. Common salt is then further purified.

. Birds and insects are the natural agents for pollination. 

2. Nowadays farmers use pesticides to control pests on crops. 

3. The enormous use of pesticides kills insects also. 

4. It effects pollination. 

5. Crop yield become reduced particularly in sun flower crop. 

6. The rate of pollination is reduced because of lack of insects in the fields. 

7. Think! How we destroy our beautiful nature.

1. Plants will not have enough space to grow freely. 

2. They will not get adequate amounts of nutrients and water. 

3. They do not obtain healthy growth.

Death comes to all. It spares none. It treats the mighty and the weak equally. It reduces everyone to dust. Therefore, it is useless to boast of one’s power or wealth. Only our good actions remain after our death. Therefore, we should always be just in our actions.

1. Roots, stems and leaves are called the Vegetative parts of a plant. 

2. Flowers are there Productive parts of the plant. 

3. Reproduction through the vegetative parts of the plant is known as Vegetative propagation. 

4. The scars on the potato plant is called eyes. 

5. The small bulb – like projection from the yeast cell is called bud.

Correct option is (iv) death

Procedure : 

1.  Take a rectangular shaped (3″ x 6″) Acrylic sheet. 
2.  Hold the Acrylic sheet with your palm without bending it. 
3.  Ask your friend to focus light with a torch light on the sheet. 
4.  Now adjust the sheet as reflected rays are caught on a wall.
5.  Now bend slowly your palm as the sheet bends inwards in the shape of concave. 
6.  Again ask your friend to focus the light. 
7.  Now bend slowly your palm as the sheet bends outwards in the shape of convex.
8.  Again ask your friend to focus the light.

Observation : 

1.  In the first case, when without bending the sheet, reflected light is not converged at one place. Because the sheet was acted as a plane mirror. 
2.  In the second case, reflected light converged at one place. Because the acrylic sheet is bent inwards and it is acted as a concave mirror. 
3.  In the third case, reflected light rays are not converged, of course they diverged with low intensity. Because the sheet was acted as a convex mirror.

Conclusion : 

Concave surfaces converge light rays and convex surfaces diverge.

No, we cannot grow all the plants by planting their stems.

1. suckers 

2. nodes of sugarcane 

3. cut the twigs with nodes and sow them 

4. eyes 

5. Bulb 

6. Ginger 

7. colocasia 

8. rose 

9. Jasmine, Jaji 

10. grafting 

11. Calyx 

12. Corolla 

13. 1st 

14. 2nd 

15. Androecium 

16. Gynoecium 

17. Stamens 

18. Ovary with style and stigma 

19. 3rd 

20. 4th

New plants grow from the stems with some vegetative propagation methods.

Yes, it matches with my observation.

In general we never found seeds in most of the hybrid banana varities. In certain varities of banana we can find small seeds. But in the wild varities we can find large sized seeds.

The minimum conditions required are a source of light to produce light, an opaque object to obstruct the light and a screen to collect the shadow.

1. This type of winged seeds are dispersed by wind. 

2. These wings help the seeds to move easily by winds to settle in a suitable place to germinate.

We may observe not only the flame, but the blurred image of entire candle.

We get blurred image on the screen due to big hole of the camera.

Two images will be formed.

If the size of the pinhole camera is increased, the image seems to be blurred.

Angle = 24°44'

Velocity of light in glass = 2 x 10⁸m/s

Angle of refraction in glass and velocity of light in glass are 35°16', 2 x 10⁸ m/s respectively.

Correct option is (D) 2694 Å, 5.8 x 10¹⁴ Hz

Correct option is (A) spherical

1. False

2. True