A student is observing standing waves. Changing the frequency of oscillation of a vertical string produces various harmonics. She changed the frequency from 30Hz to 60Hz. Which of the following must change as a result of this adjustment? Mark all that apply. a
The velocity must double
b
The wavelength must double
c
The velocity will remain the same
d
The wavelength must half
e
The velocity must half
f
The wavelength will remain the same

a small object of mass 3.66 g and charge -17.6 µc is suspended motionless above the ground when immersed in a uniform electric field perpendicular to the ground. what are the magnitude and direction of the electric field?

b would be the answer

the working equation for the angular size is the product of the physical size and 360 degrees divided by the product of two pi and distance from earth. the minimum size would be 0.559 degrees while the maximum size would be 0.49 degrees. 

conduct current i mean it makes sense