किसी द्रव का पृष्ठ तनाव (Surface tension) निम्नलिखित में से किस बल के कारण उत्पन्न होता है?

When a bottle of perfume is kept open in a corner of a room, its fragrance is soon felt in all parts of the room. This occurs due to which phenomenon?

The quantity of matter contained in a substance is termed as:

What is the ability of a material, particularly a metal, to resist surface wear, scratching, and abrasion called?