Answer:
Dolphins use a method called echolocation to detect things such as obstacles and prey in the water. If a dolphin swimming in seawater at 25°C sends a 220-dB click with a frequency of 120.0 Hz, and then detects the reflection of the click exactly one-twentieth of a second later, approximately how far away is the object?
Answer is (3) - ratio of neutrons to protons.
Isotopes are the atoms which have same atomic number but have different number of neutrons of same element.
Atomic nucleus can be stable or unstable. The stability of isotopes is based on neutron/ proton ratio. Unstable nucleus tries to become stable by emitting radiations.
Answer:
= 
Explanation:
Tollens test is carried out to perceive difference between aldehydes and ketones on the basis of their capability to oxidized easily.
when Tollens react with aldehyde (heptanal) , a silver mirror is form on inner side of container.
The reaction between tollens and heptanal is given as
= 
Heat= mass * change in temperature* specific heat
specific heat=409 J/kg K