Answer:
Atomic number = 25 protons
Mass number = ( 25 + 30 ) = 55
In case of heptane (C7H16) the following structural isomers are possible
shown in figure
a. 1-sec-butylpropane : this is actually 3-methyl hexane
b. 4-methylhexane : this is actually 3-methylhexane
c. 2-ethylpentane : this is actually 3-methyl hexane
d. 1-ethyl-1-methylbutane: 3-methylhexane
e. 3-methylhexane: correct IUPAC
f. 4-ethylpentane: This is actually 3-methylhexane
Hence all represent single isomer
That would be
Answer (B), my friend
A surface wave is a combination of a transverse wave and a longitudinal wave. A transverse wave is a wave in which particles of the medium move up and down perpendicular to the direction of the wave. A longitudinal wave is a wave in which particles of the medium move parallel to the direction of the wave. In a surface wave, particles of the medium move up and down as well as back and forth. This gives them an overall circular motion.
The gravitational interaction between the earth and the moon