Q.1) Choose the correct option.
Which of the following is true?
(A)The baby is male/female is determined by mother's chromosome.
(B) The baby is male/female is determined by father's chromosome.
(C) Pair of Mother's chromosome is X-Y.
(D) Pair of Father's chromosome is X-X.
Q.2) 'In a tug-of-war, when the two teams are pulling the rope, a stage comes when the
rope does not move to either side at all'. Which of the following is the correct reason
for this?
(A) Both teams have the same number of members.
(B) There is a lot of competition going on between the two teams.
(C) The net force of forces acting in opposite directions is equal to the difference
between the two forces.
(D) The net force of forces acting in opposite directions is equal to the sum of the two
forces.
Q.3) Which of the following does not happen due to friction?
(A) A nail is fixed in the wall
(B) fire can be produced with a matchstick.
(C) heat is produced.
(D) durability of chappals increases.
Q.4) Which of the following are the benefits of special shape of an aeroplane?
(i) Fluid friction is reduced.
(ii) Fluid friction is increased.
(iii) Energy loss is as low as possible,
(iv) An aeroplane can fly like a bird,
(A) (i), (ii) . (B) (i), (ii), (iii) . (C) (i), (iii), (iv) . (D) (i), (ii), (iii), (iv)
Q.5) Which of the following musical instruments uses air column to produce sound?
(A) Veena (B) manjira(cymbals) (C)Flute (D) tabla
Q.6) Which of the following is false for loudness of sound and amplitude of vibration?
(A) Loudness of sound depends on its amplitude of the vibration.
(B) Loudness of a sound is proportional to the square of the amplitude of the vibration
producing the sound.
(C) When the amplitude of vibration is large, the sound produced is loud.
(D) If the amplitude of vibration is increased to 4 times of its initial value, then the
loudness of sound becomes 6 times of its initial value.
Due to which of the following reasons Chromium plating is done on some objects
Q.7) used in everyday life?
(1) Chromium is cheaper.
(ii) Chromium has a shiny appearance.
(iii) Chromium does not corrode.
(iv) Chromium resists scratches.
(A) (ii), (ii) (B) (ii), (iii), (iv) (C) (iii), (iv) (D) (i). (ii), (iii), (iv)
Answers
Explanation:
1 b
2 c
3 d
4 c
5 c
6 d
7 c.
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Answer:
Q.1) (B) The baby is male/female determined by the father's chromosome.
Q.2) (C) The net forces acting in opposite directions is equal to the difference between the two forces.
Q.3) (D) durability of chappals increases.
Q.4)(C) (i), (iii), (iv)
Q.5)(C) Flute uses air column to produce sound.
Q.6)(D) If the amplitude of vibration is increased to 4 times its initial value, then the loudness of sound becomes 6 times its initial value.
Q.7) (B) (ii), (iii), (iv)
Explanation:
Q.1 The sex determination in humans is of XX-XY type. When the sperm (gamete from the father) carrying the X chromosome fuses with the egg cell, a female (XX) zygote is formed, and when sperm with the Y chromosome fuses, a male (XY) zygote is formed. Therefore, the determination of whether the baby is male/female is based on the father's chromosome.
Q.2 In tug-of-war, the two teams pull the rope in opposite directions. Therefore, when the rope is not moving, the net forces acting in the opposite directions is equal to the difference between the two forces.
Q.3 Of the given options, the increase in durability of chappals does not occur due to friction. The nail is fixed in the wall, the fire is produced with a matchstick, and the heat production all happens due to friction.
Q.4 The benefits of the special shape of an airplane are as follows- fluid friction is reduced, energy loss is low and it can fly like a bird due to its streamlined body similar to that of a bird.
Q.5 The musical instrument that uses an air column to produce sound is the flute. While the veena produces sound due to the vibration of the strings and manjira and tabla are the percussion instruments.
Q.6 Loudness is directly proportional to the amplitude of the sound vibration and it is equal to the square of the amplitude.
Q.7 Chromium plating is a technique of electroplating a chromium layer onto metal in order to prevent corrosion, resist scratches, and for decorative purposes.