Chapter

Describe with the help of a diagram an instrument which can be used to detect a charged body.

Sketch larynx and explain its function in your own words.

What is metamorphosis? Give examples.

Make a labelled diagram of a candle flame.

The following Table shows the total power shortage in India from 1991– 1997. Show the data in the form of a graph. Plot shortage percentage for the years on the Y-axis and the year on the X-axis.

Arrange the following boxes in proper order to make a flow chart of sugarcane crop production.

Make sketches of animal and plant cells. State three differences between them.

What is a constellation? Name any two constellations.

Describe the construction of a kaleidoscope.

Make a sketch of the human nerve cell. What function do nerve cells perform?

Write short notes on the following:
(a) Cytoplasm
(b) Nucleus of a cell

Explain how CO₂ is able to control fires.

Indicate whether the following statements are True (T) or False (F).
(a) Unicellular organisms have one-celled body. (T/F)
(b) Muscle cells are branched. (T/F)
(c) The basic living unit of an organism is an organ. (T/F)
(d) Amoeba has irregular shape. (T/F)

The process that you saw in Activity 14.7 is used for purification of copper. A thin plate of pure copper and a thick rod of impure copper are used as electrodes. Copper from impure rod is sought to be transfered to the thin copper plate. Which electrode should be attached to the positive terminal of battery and why?

The table below shows the data on likely heights of boys and girls as they grow in age. Draw graphs showing height and age for both boys and girls on the same graph paper. What conclusions can be drawn from these graphs?

Fill in the blanks with suitable words.
(a) Time taken by an object to complete one oscillation is called ................... .
(b) Loudness is determined by the .........................of vibration.
(c) The unit of frequency is..........................
(d) Unwanted sound is called ......................... .
(e) Shrillness of a sound is determined by the ................. of vibration.

Where are chromosomes found in a cell? State their function.

What are weeds? How can we control them?

Match the terms of column I correctly with the phrases given in column II.
       Column I                 Column II
  (i) Polyester           (a) Prepared by using wood pulp
  (ii) Teflon                (b) Used for making parachutes and stockings
  (iii) Rayon              (c) Used to make non-stick cookwares
  (iv) Nylon               (d) Fabrics do not wrinkle easily

Why does the increased level of nutrients in the water affect the survival of aquatic organisms?