Answer:
Answer: No of anti-nodes increases
Answer: wavelength remains same.
Answer: fundamental frequency decreases
Step-by-step explanation:
a)
The number of nodes (n) would have (n-1) anti-nodes.
The relation of Length of string with n is given below:

Hence, n and L are directly proportional so as string length increases number of nodes and anti-nodes also increases.
Answer: No of anti-nodes increases
b)
Wavelength is dependent on the frequency:

The speed v of the string remains same through-out and frequency of generator is unchanged!
Hence according to above relationship lambda is unchanged.
Answer: wavelength remains same.
C
Fundamental frequency equates to 1st harmonic that 2 nodes and 1 anti-node. Wavelength is = 2*L
Hence, if L increases wavelength increases
Using relation in part b
As wavelength increases fundamental frequency decreases
Answer: fundamental frequency decreases