Would the bulb glow in the circuit shown in Fig. 12.15?
The bulb would not glow in the circuit because here the electric circuit is not complete. For the bulb to glow, circuit must be complete so that electric current pass through it. A glowing bulb shows that there current is flowing from the positive terminal of the battery to the negative terminal.
Diagram:
Explain why the bulb would not glow in the arrangement shown in Fig. 12.13.
Using the "conduction tester" on an object it was found that the bulb begins to glow. Is that object a conductor or an insulator? Explain.
Would the bulb glow after completing the circuit shown in Fig. 12.14 if instead of safety pin we use an eraser?
Mark 'True' or 'False' for following statements:
(a) Electric current can flow through metals.
(b) Instead of metal wires, a jute string can be used to make a circuit.
(c) Electric current can pass through a sheet of thermo Col.
Complete the drawing shown in Fig 12.14 to indicate where the free ends of the two wires should be joined to make the bulb glow.
Why should an electrician use rubber gloves while repairing an electric switch at your home? Explain.
Fill in the blanks :
(a) A device that is used to break an electric circuit is called _______________.
(b) An electric cell has _______________ terminals.
The handles of the tools like screwdrivers and pliers used by electricians for repair work usually have plastic or rubber covers on them. Can you explain why?
What is the purpose of using an electric switch? Name some electrical gadgets that have switches built into them.
(a) Which kind of garbage is not converted into compost by the redworms?
(b) Have you seen any other organism besides redworms, in your pit? If yes, try to find out their names. Draw pictures of these.
Rearrange the boxes given below to make a sentence that helps us understand opaque objects.
To walk through a waterlogged area, you usually shorten the length of your dress by folding it. Can this change be reversed?
Do you find that all living beings need the same kind of food?
Name the major nutrients in our food.
Classify the following fibres as natural or synthetic:
nylon, wool, cotton, silk, polyester, jute
Name five objects which can be made from wood.
Why do we need to separate different components of a mixture? Give two examples.
Correct the following statements and rewrite them in your notebook.
(a) Stem absorbs water and minerals from the soil.
(b) Leaves hold the plant upright.
(c) Roots conduct water to the leaves.
(d) The number of petals and sepals in a flower is always equal.
(e) If the sepals of a flower are joined together, its petals are also joined together.
(f) If the petals of a flower are joined together, then the pistil is joined to the petal.
Fill in the blanks:
(a) Joints of the bones help in the ——————— of the body.
(b) A combination of bones and cartilages forms the _______ of the body.
(c) The bones at the elbow are joined by a ______________________ joint.
(d) The contraction of the _____________ pulls the bones during movement.
Fill in the blanks:
(i) One metre is ______________ cm.
(ii) Five kilometre is ______________ m.
(iii)Motion of a child on a swing is ______________.
(iv)Motion of the needle of a sewing machine is ______________.
(v) Motion of wheel of a bicycle is______________.
Where are poles of a bar magnet located?
Rearrange the boxes given below to make a sentence that helps us understand opaque objects.
Do you find that all living beings need the same kind of food?
Give examples to explain the difference between changes that can or cannot be reversed.
Is it possible to separate sugar mixed with wheat flour? If yes, how will you do it?
Match the items in Column I with one or more items of Column II.
Column I Column II
Upper jaw have fins on the body
Fish has an outer skeleton
Ribs can fly in the air
Snail is an immovable joint
Cockroach protect the heart
shows very slow movement
have a streamlined body
What is the function of a stem in a plant?
A drawing sheet changes when you draw a picture on it. Can you reverse this change?
In which part of a flower, you are likely to find the ovary?