Density= mass/volume
step one :
convert m3 to ml
1m^3 =1000000ml
0.250m^3 x1000000=250000ml
step two: convert mg to g
1mg=0.001g, therefore 4.25 x108mg=0.459g
density is therefore= 0.459g/250000=1.836 x10^-6g/ml
Answer:
The cooler water is denser
Explanation:
Convection drives the boiling of water placed on a stove in a kettle.
During convection, heat is circulated by density differences in portions of a fluid.
Convection is a form of heat transfer in fluids especially gas and liquid.
- In boiling water, the heat is supplied to the base of the stove.
- The water at the bottom on heat becomes lighter as the molecules gain more kinetic energy.
- The colder part of the water on top sinks to replace the less dense on below.
- This exchange sets up convection cells in the kettle.
Answer:
75000 Hz
Explanation:
f = V / λ (f= frequency, v=velocity of wave, lambda= wavelength)
alternatively, f = c / λ (f= frequency, c= speed of light- 3.00x10^8 m/s, lambda= wavelength)
f= [3.00x10^8 m/s]/[4000 m]
=75000 Hz
Answer is (4) - Pb.
According to the reactivity series of elements
- the elements which are above the hydrogen are more reactive than hydrogen.
- the elements which are below the hydrogen are less reactive than hydrogen.
Among the given choices, only Pb is placed above the hydrogen in the reactivity series and rest are below the hydrogen.
Hence, Pb is more active than hydrogen.
