Question 1

Mirrors used to concentrate sunlight to generate high temperatures in solar furnaces are ____ mirrors.
A) convex
B) concave
C) plane
D) semi silvered

Question 2

The accommodation power of the eye lens of a young man, whose far point is infinity, can vary from 40 D to 44 D. Then the distance of the retina from the eye lens is ____ cm.
A) 0.025
B) 5
C) 2.5
D) 0.05

Question 3

When 2 identical resistors of resistance 10 are connected in parallel, the resultant resistance is ____ .
A) 20
B) 10
C) 5
D) 15

Question 4

A circular coil is aligned horizontally and certain amount of current flows though the coil in clockwise direction when viewed from above the coil. The direction of magnetic field at the centre of the coil due to the current is ____.
A) vertically downward
B) vertically upward
C) towards east
D) towards west

Question 5

Fe_(s) + H₂O(steam) → Fe₂O₃(s) + H₂↑ is not a balanced equation because the ____.
A) number of hydrogen atoms are unequal  on the reactant and product side
B) number of iron atoms are more on the reactants than on the products side
C) physical states mentioned are not correct
D) number of iron and oxygen atoms are unequal on the reactant and product side

Question 6

Elements X and Y have the following configurations.
 X–2,6 and Y–2,8,8,2

The nature of bond between X and Y is ____.

A) ionic
B) covalent
C) coordinate
D) polar

Question 7

A, B, C are elements of Dobereiner's triad. If the atomic mass of A is 40.1 and that of C is 137.3, the atomic mass of element B is ____.
A) 177.4
B) 97.2
C) 88.7
D) 80.2

Question 8

During anaerobic respiration, the respiratory substrates are incompletely broken down to release ____.
A) methyl alcohol
B) ethyl alcohol
C) propyl alcohol
D) butyl alcohol

Question 9

Phytohormones used in development of male flowers on genetically developed female plants are____.
A) cytokinins
B) auxins
C) gibberellins
D) 2 , 4 - D

Question 10

AIDS is a sexually transmitted disease.
A) True
B) False