Answer: A and D, I believe
Explanation:
Answer:
8.99×10^-7m
Explanation:
The wavelength can be calculated using the expression below
E=hcλ
Where E= energy= 2.21 x 10^-19 J.
C= speed of light= 3x10^8 m/s
h= planks constant= 6.626 × 10^-34 m2 kg / s
E=hcλ
λ= E/(hc)
Substitute for the values
λ=( 2.21 x 10^-19 )/(6.626 × 10^-34 × 3x10^8 )
= 8.99×10^-7m
Answer:

Explanation:
Hello,
In this case, for latent heat (phase change) we need to consider the enthalpy associated with the involved process, here, melting or fusion; thus, the enthalpy of fusion of copper is 13.2 kJ/mol, therefore, the heat is computed as:

Nevertheless, since the given enthalpy is per mole of copper, we need to use its atomic mass to perform the correct calculation as follows:

Which is positive as it needs to be supplied to the system.
Best regards.
Answer:
I didn't do the observation so I can't help sorry
Answer:
Given that W=mg:
The weight of the box would be 50 N taking the value of 'g' as 10ms-2. Taking the value of 'g' as 9.8ms-2, the weight of the box would be 49 N.
(N = Newtons)