Isotopes of an element have the same atomic number but different mass numbers (The mass number represents the sum of the number of protons and neutrons of an element.).
Therefore, The correct option is (c) different number of neutrons.
| A | B |
|---|---|
| (i) broke out | (a) an attitude of kindness, a readiness to give freely |
| (ii) in accordance with | (b) was not able to tolerate |
| (iii) a helping hand | (c) began suddenly in a violent way |
| (iv) could not stomach | (d) assistance |
| (v) generosity of spirit | (e) persons with power to make decisions |
| (vi) figures of authority | (f) according to a particular rule, principle, or system |
ABC is a triangle in which altitudes BE and CF to sides AC and AB are equal (see Fig). Show that
(i) ∆ ABE ≅ ∆ ACF
(ii) AB = AC, i.e., ABC is an isosceles triangle.

Section | Number of girls per thousand boys |
|---|---|
Scheduled Caste (SC) | 940 |
Scheduled Tribe (ST) | 970 |
Non-SC/ST | 920 |
Backward districts | 950 |
Non-backward districts | 920 |
Rural | 930 |
Urban | 910 |
(i) Represent the information above by a bar graph.
(ii) In the classroom discuss what conclusions can be arrived at from the graph.