Which of the following statements is not true?
a. the intensity of the center maximum is the largest in a single slit interference pattern
b. a monochromatic light source is one that consists of many colors
c. the intensity of the center maximum is the largest in a double slit interference pattern

The Greek root "mono" means alone/single/one. This gives away the answer rather easily. A monochromatic light source contains just one color.

Choice B

the bal will not change its velocity.

the only real purpose of sputnik 1 was to beat the us into space. we were getting close to launching a useful satellite, explorer 1 - which launched on january 31, 1958. the ussr had to beat that, so they launched sputnik 1 on october 4, 19