Answer:
Explanation:
Q = m c Δt
heat withdrawn to lower temperature by 40° C
Q = 1 X 1000 X 40 = 40,000 calories.
Q = mL
heat withdrawn to freeze water at 0°C to ice
= 1 x 80000 = 80,000 calories
total heat to be withdrawn = 120,000 calories. = 120,000 x 4.2 = 504 ,000 Joules.
Answer:
It can be said to be reliable although it is not valid
Explanation:
This is because Reliability means an indicator of consistency, A measure should produce similar or the same results consistently if it measures the same quantity. So does the thermometer measures over 5days but it is not valid because it deviates from the real value
Answer:
evaporation, melting, freezing
Explanation:
matter is a solid, gas, or liquid
evaporation turns a liquid to gas
melting changes a solid to liquid
freezing changes a liquid to a solid
Answer:
a) v = 1.075*10^7 m/s
b) FB = 7.57*10^-12 N
c) r = 10.1 cm
Explanation:
(a) To find the speed of the alpha particle you use the following formula for the kinetic energy:
(1)
q: charge of the particle = 2e = 2(1.6*10^-19 C) = 3.2*10^-19 C
V: potential difference = 1.2*10^6 V
You replace the values of the parameters in the equation (1):

The kinetic energy of the particle is also:
(2)
m: mass of the particle = 6.64*10^⁻27 kg
You solve the last equation for v:

the sped of the alpha particle is 1.075*10^6 m/s
b) The magnetic force on the particle is given by:

B: magnitude of the magnetic field = 2.2 T
The direction of the motion of the particle is perpendicular to the direction of the magnetic field. Then sinθ = 1

the force exerted by the magnetic field on the particle is 7.57*10^-12 N
c) The particle describes a circumference with a radius given by:

the radius of the trajectory of the electron is 10.1 cm
Like a lot of other things, (gravity, sound, electrostatic force), brightness also decreases as the square of the distance.
When the source moves to a new position that's 4 times as far away, its apparent brightness becomes (1/4^2) its original value.
That's 1/16 .