The proposed models of an atom given in this chapter-
Thomson’s model | Rutherford’s model B | Bohr’s model |
|---|---|---|
| An atom consists of a positively charged sphere and the electrons are embedded in it. | An atom consists of a positively charged center in the atom called the nucleus. The mass of the atom is contributed mainly by the nucleus. | Bohr agreed with almost all points as said by Rutherford except regarding the revolution of electrons for which he added that there are only certain orbits known as discrete orbits inside the atom in which electrons revolve around the nucleus. |
| The negative and positive charges are equal in magnitude. As a result the atom is electrically neutral. | The size of the nucleus is very small as compared to the size of the atom. | While revolving in its discrete orbits the electrons do not radiate energy. |
A driver of a car travelling at \(52\) \(km \;h^{–1}\) applies the brakes Shade the area on the graph that represents the distance travelled by the car during the period.
Which part of the graph represents uniform motion of the car?
| 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.
