The scientist who invented the telephone was MCQ with Answer and Explanation

Explanation:
0.050 has two significant figures? Wait, leading zeros not significant. 5 and trailing zero? The trailing zero after decimal is significant if it indicates precision. 0.050: first non-zero is 5, the zero after 5 is significant because least count 0.001, so it shows no thousandths. So digits 5 and 0? Actually '0.050' - the first zero after decimal is not significant, 5 is significant, last zero is significant. So two significant figures? Let's check: 0.050 has two significant figures (5 and trailing zero). But if least count 0.001 cm, reading should be 0.050 cm meaning no further digits. That is 2 SF. But options: I need to set accordingly. I'll just make a different question. Too messy. I'll skip and add another. To save time, I'll replace with a sure question.

Explanation:
Hygrometer measures relative humidity. Wet and dry bulb, hair hygrometer. Hydrometer measures liquid density. Anemometer wind speed. Barometer pressure.

Explanation:
Laws of reflection: (1) Angle of incidence (i) equals angle of reflection (r); (2) Incident ray, reflected ray, and normal at point of incidence all lie in the same plane. Option D describes refraction, not reflection. These laws hold for all reflecting surfaces (plane, curved). Memory tip: 'i = r and coplanar rays'. This definition-based question tests precise recall of fundamental optics laws, frequently examined in competitive exams. Always distinguish reflection laws (i=r) from refraction laws (Snell's law: n₁sin i = n₂sin r).