If the frequency of sound is doubled, how will its speed change? how will its wavelength change?

From the given equation we can deduce what changes will occur if the frequency of the sound is doubled

V= f (λ)

Speed = frequency. Wavelength  

When the frequency is doubled, speed will not change. Because speed depends on factors like temperature, air pressure, density of the gas. Since all these factors are unchanged thus speed will remain unchanged

Frequency is the number of waves produced per second. Frequency and wavelength are inversely proportional .Thus, if the frequency is doubled the wavelength would be halved.

the current is 0.6

voltage ÷ resistance = current

so 12 ÷ 20 = 0.6

see earlier