A) frequency increases and speed decreases

B) frequency is the same but the wavelength is smaller in water than in air

C) frequency is same but the wavelength is larger in water than in air

D) frequency and speed both decreases

(A) volume of rainfall

(B) cloud volume and speed

(C) salinity of sea

(D) all options are correct

(A)  rectilinear propagation of light

(B) reflection

(C) refraction

(D) total internal reflection

(A) Democritus

(B) Proust

(C) Lavoisier

(D) John Dalton

(A) south

(B) north

(C) east

(D) west

(A) gravitational pull

(B) rotation of earth

(C) revolution of earth

(D) uneven heating of earth

(A) activator

(B) fuse

(C) explosive

(D) power source

(A) rubber

(B) plastic

(C) aluminum

(D) wood

(A) the time of ascent < the time of descent

(B) the time of ascent > the time of descent

(C) the time of ascent = the time of descent

(D) none of these

(A) forward

(B) backward

(C) sideways

(D) none of these