Which of the following substances is found in green henna, due to which it turns red?

If the mass of a body is 'm' on the surface of the earth, its mass on the surface of the moon will be :

The sky appears blue due to its?

Goiter / excessive growth of thyroid gland causes by the deficiency of:

Speed of sound is maximum?

Iron pipes, from which water is supplied, are coated with zinc (Zn) to prevent rusting. This layering process is called?

Insulin was invented by?

By which instrument the purity of milk is measured?