Is Matter Around Us Pure ? — Science STD 9 — Question

Mass of one atom of oxygen is formul:

The acceleration produced by a force of 5N acting on a mass of 20kg in m/s² is:

Which of the following are isotopes and which are isobars?
Argon (Ar), Deuterium (D), Calcium (Ca), Tritium (T), Protium (P)

Neon and chlorine have atomic numbers 10 and 17 respectively. Their valencies will be ______ and ______ respectively:

Which one is not a source of carbohydrate?

1. Rice
2. Millets
3. Sorghum
4. Gram

When a gas jar containing colourless air is kept upside down over a gas jar full of brown-coloured bromine vapour, then after sometime, the brown colour of bromine vapour spreads into the upper gas jar making both the gas jars appear brown in colour. Which of the following conclusion obtained from these observations is incorrect?

Which of the following statements is not true about an atom?

Four students A, B, C and D find the acceleration due to gravity at the top of Ooty, Nainital, Mount Everest and Shimla. The acceleration due to gravity is the least:

Water drops fall at regular intervals from a roof at of 125m from the ground. At an instant when 11th drop is about leave the roof and 1st drop is at a height of 45m from the ground at that instant the dist of 10th drop from the roof is (g=10 m/ s²)

Who has divided Prokaryota (Monera) into Archaea and Eubacteria?

1. Haeckel.
2. Copeland.
3. Woese.
4. Whittaker.