Question : Law of independent assortment can be proved on the basis of which of the following ratios?
(a) 1 : 3 : 1 (b) 2 : 1 : 1 (c) 9 : 3 : 3 : 1 (d) 2 : 1
Answer : C
Question : Parturition is
(a) the complete development of fetus, from the initial stage of conception till the birth of the young one
(b) the act of expelling the full-term young one from the mother’s uterus at the end of gestation
(c) the implantation of the embryo in the uterus
(d) none of these.
Which among the following statements are true for sexual reproduction in flowering plants?
(i) It requires two types of gametes.
(ii) Fertilisation is a compulsory event.
(iii) It always results in formation of zygote.
(iv) Offspring formed are clones.
(a) (i) and (iv) (b) (i), (ii) and (iv)
(c) (i), (ii) and (iii) (d) (i), (iii) and (iv)
Answer : B
(c) : Clones are identical to parent plant and are formed in case of asexual reproduction.
Question : What will happen if deer gets extinct from the food chain given below?
Grass →Deer →Tiger
(a) The population of tiger increases.
(b) The population of grass decreases.
(c) The tiger will start eating grass.
(d) The population of tiger decreases and the population of grass increases
Answer : D
Question : What should be the characteristics of a heating element?
Answer : A heating element should have the following characteristics :
(a) It should have high resistivity.
(b) It should have high melting point, and should not burn/oxidise at higher temperature.
Question : Write any one method to induce current in a coil.
Why two magnetic lines of force never intersect each other?
By keeping the magnet in a fixed position and moving the coil towards and away from the magnet, we can induce current in the coil.
The direction of magnetic field (B) at any point is obtained by drawing a tangent to the magnetic field line at that point. In case, two magnetic field lines intersect each other at a point P as shown in figure, magnetic field at P will have two directions, shown by two arrows, drawn to each magnetic field line at P, which is not possible.