Answer: Electromagnetic waves can transfer energy through empty space.
Explanation:
Electromagnetic waves are formed when an electric field comes in contact with a magnetic field. The electric field and magnetic field of an electromagnetic wave are perpendicular to each other. They are also perpendicular to the direction of the wave.
Electromagnetic waves travel with speed of light in vacuum.
Electromagnetic wave does not need a medium to propagate or travel from one place to another. Electromagnetic waves are 'transverse' waves which means that they are measured by their amplitude and wavelength.
Electromagnetic waves do not lose energy when they travel and thus can travel far from its source.
Explanation:
It is given that, a mass attached to a spring oscillates and completes 53 full cycles in 28 s. Frequency of the system is given by the number of oscillations or vibrations per second. Here, the frequency of this system is given by :
f = 1.89 Hertz
The relationship between the frequency and the time period of the spring is inverse i.e.
T = 0.52 seconds
Hence, this is the required solution.
Explanation:
Density is defined as the ratio of the mass to the volume. The expression for density is:
The Si unit for density is kg/m³
The dimensional expression for density = [ML⁻³]
Specific volume is defined as the ration of the volume to the mass. It is the reciprocal of density.
The BG unit of specific volume is ft³ / lb.
Answer:
2000 N
Explanation:
20 km/h = 5.56 m/s
100 km/h = 27.78 m/s
F = ma
F = m Δv/Δt
F = (200 kg + 80 kg) (27.78 m/s − 5.56 m/s) / (3 s)
F = 2074 N
Rounded to one significant figure, the force is 2000 N.
Answer:
20g
Explanation:
Given parameters:
Quantity of heat = 240calories
Initial temperature = 80°C
Final temperature = 68°C
Unknown:
Mass of water = ?
Solution;
To solve this problem, we use the expression:
Q = m c (t₂ - t₁)
Q is the quantity of heat
m is the mass
c is the specific heat = 1 cal/g°C
t₂ is the final temperature
t₁ is the initial temperature
Insert the parameters and solve;
Change in temperature is an absolute value
240 = m x 1 x (68 - 80)
m = 20g
