η = 13.8 lm/W. The luminous efficacy of a incandescent lightbulb that produces 830 lumens and consumed a power of 60 W is 13.8 lm/W.
The luminous efficacy of a light source is the relationship between the luminous flux (in lumens) emitted by a light source and the power (in watts). The luminous efficacy of a light source or luminous efficiency measures the part of electrical energy that is used to illuminate and is obtained by dividing the luminous flux emitted by the electrical power consumed. Luminous efficiency is expressed in lumens per watt (lm / W). It is given by the relation:
η = F / P. Where F is the luminous flux, and P is the power consumed by the light source.
The efficacy of a 60.0 W incandescent lightbulb that produces 830 lm is:
η = 830 lm / 60 W
η = 13.8 lm/W
The mass number of a nucleus (except Hydrogen) is: number of protons + number of neutrons.
A=Z+N
A=mass number=protons + neutrons.
Z=atomic number=number of protons.
N=number of neutrons.
In the case of Hydrogen it depends of isotope of Hydrogen .
the hydrogen has three isotopes,
protium : A=Z, because N=0
deuterium: A=Z+N; N=1
tritium: A=Z+N; N=2
Answer:
There are three types of material as per the condition of charge flow
1) Conductor
2) Insulator
3) Semiconductor
1) Conductors
As we know that conductors are those which offer very small resistance to the flow of charge
Resistivity of the conductors are very small
2) Insulators
These type of materials offer large resistance to the flow of charges and it will not pass the current through it
So resistivity of the insulators are large as compared to conductors
Answer:
the strength of the magnetic field is 3 x 10⁻⁵ T
Explanation:
Given;
velocity of the cosmic ray, v = 5 x 10⁷ m/s
force experienced by the ray, f = 1.7 x 10⁻¹⁶ N
angle between the ray's velocity and the magnetic field, θ = 45⁰
The strength of the magnetic field is calculated as;
Therefore, the strength of the magnetic field is 3 x 10⁻⁵ T
