Answer: i think c
Explanation:QA: “What is ordinary glass made of ?”
Glass is mostly silica, or silicon dioxide, present as quartz in many types of sand. Pure silica forms a highly transparent glass, but has a very high melting or softening temperature, around 1700°C. Even at such high temperatures it is highly viscous and difficult to work. Its use is largely confined to applications requiring high transparency to ultra-violet and infra-red radiation, stability at elevated temperatures or low thermal expansion coefficient.
“Ordinary glass” windows and drinking vessels are typically made from soda-lime glass, containing silica with around 25% sodium, calcium and other oxides, which together reduce the softening temperature to roughly 500–600°C
Answer:

Explanation:
As we know that the position of maximum intensity on the screen is given as

here we know that
= wavelength
L = distance of the screen
d = distance between two slits
now we know that the position of 8th maximum intensity is same as that of 9th maximum on the screen
so we have

so here we have


Answer: a) 19.21m b) 3.92secs
Explanation:
a) Maximum height reached by the object is the height reached by an object before falling freely under gravity.
Maximum height = U²/2g
U is the initial velocity = 19.6m/s
g is acceleration due to gravity = 10m/s²
Maximum Height = 19.6²/2(10)
H = 19.21m
b) The time elapsed before the stone hits the ground is the time of flight T= 2U/g
T= 2(19.6)/10
T = 39.2/10
Time elapsed is 3.92secs
AnMolar mass of CuCO3 = 123.5549 g/mol
This compound is also known as Copper(II) Carbonate.
Convert grams CuCO3 to moles or moles CuCO3 to grams
Molecular weight calculation:
63.546 + 12.0107 + 15.9994*3
Percent composition by element
Element Symbol Atomic Mass # of Atoms Mass Percent
Copper Cu 63.546 1 51.431%
Carbon C 12.0107 1 9.721%
Oxygen O 15.9994 3 38.848%
Explanation:
as the surface area increases the rate of reaction also increases.
Explanation: