incorrect answer in ER??

[izzahzainab]

http://www.xtremepapers.me/CIE/index.ph ... 3_qp_2.pdf

its june 2003, physicsppr 2. check Q11(b)(ii) the time taken for the ultrasound pulse to reach the sea bed,

 

[leosco1995]

The answer looks fine to me. Look at the CRO trace and notice that it takes 2 divisions for the pulses to be sent and reflected back from the sea-bed. So that means it takes one division to reach the sea bed. The answer should be 0.1s.

 

[izzahzainab]

ooooohhhhh, 0.2 needs to be divided by two, i forgot that !! thanku!