All categories

3 years ago

Why doesn’t a convection current form when a liquid is heated at the top?

1 answer:

5 0

If the heating is done on one small area on the top, there will be convection. If the heating is restricted to a small fraction of the heating area, then within that area the heating will go deeper than anywhere else on the surface. Then unheated area will have a shallower region of high temperature. Then some convection will occur in the deeper layers, causing some motion on top.

This happens quite a bit during welding. Convection is very significant in welding, even when the heating is from the top.

You might be interested in

What is photosynthesis?

motikmotik

Explanation:

Photosynthesis is the process by which plants use sunlight, water, and carbon dioxide to create oxygen and energy in the form of sugar.

5 0

3 years ago

Read 2 more answers

Pam observed many small earthworms in the backyard of her house after a heavy rain. What most likely formed the earthworms?

AlekseyPX

Answer: Option (b) is the correct answer.

Explanation:

When it rains, then mud in the backyards become wet. It is known that earthworms live inside earth and diffusion of oxygen gets slower through water than through air.

As a result, supply of oxygen to the worms decreases in wet mud hence, they come to the surface in order to breathe.

Thus, we can conclude that wet mud in the backyard most likely formed the earthworms.

4 0

4 years ago

If our eyes could see a slightly wider region of the electromagnetic spectrum, we would see a fifth line in the Balmer series em

erica [24]

Answer: Wavelength associated with the fifth line is 397 nm

Explanation:

$E=\frac{hc}{\lambda}$

$\lambda$ = Wavelength of radiation

E= energy

For fifth line in the H atom spectrum in the balmer series will be from n= 2 to n=7.

Using Rydberg's Equation:

$\frac{1}{\lambda}=R_H\left(\frac{1}{n_i^2}-\frac{1}{n_f^2} \right )\times Z^2$

Where,

$\lambda$ = Wavelength of radiation

$R_H$ = Rydberg's Constant = $10973731.6m^{-1}$

$n_f$ = Higher energy level = 7

$n_i$ = Lower energy level = 2 (Balmer series)

Putting the values, in above equation, we get

$\frac{1}{\lambda}=10973731.6\times \left(\frac{1}{2^2}-\frac{1}{7^2} \right )\times 1^2$

$\frac{1}{\lambda}=2.52\times 10^{6}m$

$\lambda}=3.97\times 10^{-7}m=397 nm$ $1nm=10^{-9}m$

Thus wavelength λ associated with the fifth line is 397 nm

7 0

4 years ago

PbO2 + 4HCl --- PbCl2 + Cl2 + 2H2O who buys electrons and who loses electrons?

SIZIF [17.4K]

Answer: Electrons are taken up by $PbO_2$ and they are lost by $HCl$

Explanation:

Redox reaction is defined as the reaction in which oxidation and reduction take place simultaneously. It is also called the reaction where the exchange of electrons takes place.

An oxidation reaction is defined as the reaction in which a chemical species loses electrons takes place. In this reaction, the oxidation state of a substance gets increased.

A reduction reaction is defined as the reaction in which a chemical species gains electrons takes place. In this reaction, the oxidation state of a substance gets reduced.

For the given chemical reaction:

$PbO_2+4HCl\rightarrow PbCl_2+Cl_2+2H_2O$