Physics Past Questions and Answers

For the wave motion represented above
The wavelength is given by

fig 10 shows a see-saw which is perfectly in balance, the weighs of the people sitting on it are 50kg, xkg and 15kg as shown, the sit at distances of 1.5, 1.5 and 2m from the pivot respectively. The vale of X is

An electrical circuit is connected up as shown above, which of the following is correct about the value of current flowing through the 1 ohm resistance?