1. The doctor heard the sound of rats. The sound was a familiar one. He heard this sound four times. The phrases are ‘Again I heard that sound from above’, ‘Again came that noise from above’, ‘Suddenly there came a dull thud as if a rubber tube has fallen’. The sounds stopped after the appearance of the snake.
2. The doctor took the following two ‘important’ and ‘earth shaking’ decisions:
(a) He would shave daily and grow a thin moustache to look more handsome.
(b) He would always keep that attractive smile on his face.
3. The doctor thought that he had a good smile when he first smiled. But when he smiled a little later, he laughed at his destiny. His life was in danger. His thoughts got changed because of the snake. He was quite near to death.
(i) The kind of person the doctor is (money, possessions)
(ii) The kind of person he wants to be (appearance, ambition)
If bromine atom is available in the form of, say, two isotopes \(^{79}Br_{35}\) (49.7%) and \(^{81} Br_{35}\) (50.3%), calculate the average atomic mass of bromine atom.
AD is an altitude of an isosceles triangle ABC in which AB = AC. Show that
(i) AD bisects BC
(ii) AD bisects ∠A.