Complete question:
A 45-mH ideal inductor is connected in series with a 60-Ω resistor through an ideal 15-V DC power supply and an open switch. If the switch is closed at time t = 0 s, what is the current 7.0 ms later?
Answer:
The current in the circuit 7 ms later is 0.2499 A
Explanation:
Given;
Ideal inductor, L = 45-mH
Resistor, R = 60-Ω
Ideal voltage supply, V = 15-V
Initial current at t = 0 seconds:
I₀ = V/R
I₀ = 15/60 = 0.25 A
Time constant, is given as:
T = L/R
T = (45 x 10⁻³) / (60)
T = 7.5 x 10⁻⁴ s
Change in current with respect to time, is given as;

Current in the circuit after 7 ms later:
t = 7 ms = 7 x 10⁻³ s

Therefore, the current in the circuit 7 ms later is 0.2499 A
Explanation:
it holds protons and neutrons together
The correct answer to your question and how to solve it is
The relation between wavelength (λ)and the frequency of electromagnetic oscillation (f) is described by the following expression: λ=c/f, where c–is the speed of light in vacuum = 3*10^8 m/s
Derive f from above: f = c/λ.How to Calculate: λ=890nm = 890*10^-9m = 8.9*10^-7m
f =3*10^8m/s Divided by 8.9*10^-7m = 0.34*10^15 s-1=3.4*10^14 s-1
So your Answer is: The frequency of radiation of wavelength 890 nm is 3.4*10^14s-1
I am absolutely sure that if something is hot, it contain thermal energy only because <span>if a given body is heated its electrons start to move very fast which means that thermal energy is being produced. Hope everything is clear! Regards!</span>