Answer:
A neutral particle made of an electron and hole
Explanation:
Exciton
It is the combination of an electron and a hole ( hole refers to the vacancy of an electron ) . And , as both the electron and the hole have the same charge but the polarity is opposite , the combination will lead to a neutral compound , i.e. , Exciton have no charge and so neutral .
It is free to move in the nonmetallic crystal and since it charge less , it is difficult to detect it directly .
1 mole ------------- 6.02x10²³ atoms
4.93 moles ------- ??
4.93 x ( 6.02x10²³) / 1 =
=> 2.96x10²⁴ atoms
There are different chemical agents which are used to study the heart rate of frog. Generally Ringer's solution is used to study frog's heart simulation. At different temperature, frogs heart speeds up or slows down while using Ringer's solution at experiment. Ringer's solution is mixture of salt solution which comprises of NaCl, KCl, CaCl2 and Na2CO3. Sometimes other chemicals like MgCl or antibiotics are also used as addition in Ringer's solution.
This solution is chiefly used to study in vitro experiments on organs and tissues like frog's heart.
Ringer's solution at 23 degree Celsius for normal heart rate
Ringer's solution at 32 degree Celsius, heart rate speed up and
Ringer's solution at 5 degree Celsius, heart rate slows down.
other chemicals also have significant effect in heart rate,
For example, Calcium ion in excess will slow down the heart rate, Atropine increases heart rate and digitalis slows down the heart rate.
Answer:
Answer B
Explanation:
By definition mixtures are combinations of substances physically prepared and physically separated. Mixtures are classified as 'homogeneous mixtures' and 'heterogeneous mixtures'. For homogeneous mixtures all components are dissolved, with solute evenly distributed throughout the solution and assumes state of solvent. 'Heterogeneous mixtures' have inconsistent properties throughout and solute concentration is not consistent throughout the mixture.
