Question

Where are TM24 (Thunderbolt) and TM10 (Hidden Power) in Black & White?

Answer 1

TM24 Thunderbolt is on the ground outside of P2 Laboratory, which is just off Route 17. The only requirements are to have Surf (after Mistralton City Gym) to access Route 17 via surfing on the water just above Nuvema Town.

The directions are difficult to give via written text, but this wiki has step-by-step screenshots that show you the exact TM location. Below is a screenshot of the TM's spot taken from the link above:

(Source: Guide Strats)

Meanwhile, TM10 Hidden Power will be given to you for free from Professor Juniper as a reward after you’ve seen at least 120 different Pokémon in the 'dex. Just visit her (usually in the lab) and she gives it to you for free.

Answer 2

TM thunderbolt can be found outside of the P2 laboratory on route one, and TM hidden power can be obtained by talking to Professor Juniper in Nuvema town after you have seen at least 100-120 unova pokemon, I don't know the exact number.