Answer:
The average rate of energy transfer to the cooker is 1.80 kW.
Explanation:
Given that,
Pressure of boiled water = 300 kPa
Mass of water = 3 kg
Time = 30 min
Dryness friction of water = 0.5
Suppose, what is the average rate of energy transfer to the cooker?
We know that,
The specific enthalpy of evaporate at 300 kPa pressure


We need to calculate the enthalpy of water at initial state


We need to calculate the enthalpy of water at final state
Using formula of enthalpy

Put the value into the formula


We need to calculate the rate of energy transfer to the cooker
Using formula of rate of energy

Put the value into the formula


Hence, The average rate of energy transfer to the cooker is 1.80 kW.
Answer:

Explanation:
From the question we are told that:
Beat frequency 
Frequency 
Generally the equation for Frequency of the violin is mathematically given by



Therefore the period of the violin string oscillations is



Answer: The force of attraction that holds two molecules is a chemical bond
Explanation:
What is Chemical bonds?
Chemical bonds are forces that hold atoms together to make compounds or molecules.
Types of chemical bonds
Chemical bonds include
1.covalent,
2. polar covalent, and
3. ionic bonds.
Atoms with relatively similar electronegativities share electrons between them and are connected by covalent bonds.
The answer is : B. The compass will spin exactly 360 Degrees
Compass will point out to the earth's magnetic field. If we change the direction of the current , we created an effect which make the compass detect the magnetic field in the exact opposite direction, that is why it will flip exactly 180 degrees
Answer:
λ = 8.88 x 10⁻⁷ m = 888 nm
Explanation:
The energy band gap is given as:
Energy Gap = E = 1.4 eV
Converting this to Joules (J)
E = (1.4 eV)(1.6 x 10⁻¹⁹ J/1 eV)
E = 2.24 x 10⁻¹⁹ J
The energy required for photovoltaic generation is given as:
E = hc/λ
where,
h = Plank's Constant = 6.63 x 10⁻³⁴ J.s
c = speed of light = 3 x 10⁸ m/s
λ = wavelength of light = ?
Therefore,
2.24 x 10⁻¹⁹ J = (6.63 x 10⁻³⁴ J.s)(3 x 10⁸ m/s)/λ
λ = (6.63 x 10⁻³⁴ J.s)(3 x 10⁸ m/s)/(2.24 x 10⁻¹⁹ J)
<u>λ = 8.88 x 10⁻⁷ m = 888 nm</u>