No one will ! it's multiple ! ! 1.) a 2.0 x 2.0 -inch slide is placed before a converging lens 21 inch in front of the focal point. if the focal length is 20. inches, how large is the image that is projected on the screen? inches 42 x 10. 40. x 40. 420 x 420 2.)four beats per second are heard when an unknown tuning fork and a 240 hz tuning fork are struck simultaneously. this same unknown tuning fork and a 250 hz tuning fork are struck. six beats are heard. its exact frequency: is 256 hz is 236 hz is 244 hz cannot be determined