Yesterday, I finish the physics Paper 33exam. After checking with my friends ,I found I made a big mistake in the first experiment. It ask to find out the period of the balance. I want to calculate it by find the time of 10complete period and use that time divide by 10. However one complete period means when the balance bounce up and then move back to original place, I calculate bounce up as a period and bounce back to original point as a second period. So actually I take the time of 5 complete periods but I didn't realize that during the exam. That makes my result value of T half of the correct T. In the following questions, I use that answer so in the following questions my result is also been affected, even my working is correct. And today, I go and ask my teacher, and she says that if there is an ECF on the mark scheme I may only lose 1or2 marks but if there isn't an ecf I will loose lots of mark. I was quite nervous now and want to ask do physics practicle exam usually have an ecf? If not I may have to retake the physics exam. QAQ Sorry for bad English because I am not an native speaker.