Sound — Science STD 9 — Question

Some boron atoms have mass number 10 and some have mass number 11. These boron atoms with different mass number are called ____________.

Plant cell wall is mainly composed of ___________. (Cellulose, Protein, Lipid)

Berseem is an important __________ crop. (Cash, Fodder, Commercial)

In neutral atoms, the number of electrons is equal to the number of ________. (Protons, Neutrons, Nucleons)

Brass is an alloy which is considered a ________. (Mixture, Element, Compound)

Name any one GM crop which is grown in India: __________. (Bt Cotton, Hybrid Rice, Golden Rice)

The anode rays obtained from hydrogen gas consist of particles called __________. (Protons, Electrons, Neutrons)

Some boron atoms have mass number 10, and some have mass number 11. These boron atoms with different mass numbers are called ____________. (Isotopes, Ions, Elements)

Isotopes have different mass numbers because their nuclei contain different numbers of _________. (Neutrons, Protons, Electrons)

In collisions and explosions, the total _______ remains constant, provided that no external _______.