Answer:
Because the light reflects multiple times until it gets to the Cassegrain focus.
Explanation:
The Cassegrain design can be seen in a reflecting telescope. In this type of design the light is collected by a concave mirror, and then intercepted by a secondary convex mirror, and sends it down to a central opening in the primary mirror (concave mirror), in which a detector is placed (Cassegrain focus)
Since, the light is reflected many times due to Cassegrain design, that leads to shorter telescopes.
Answer:
D. Test a cell phone's reception in the exact same location under various atmospheric conditions
Explanation:
Components of an experiment:
Independent variable:
A manipulated variable, in an experiment or study, whose presence or degree incurs a change in the dependent variable.
Dependent variable:
A variable which is being studied in the experiment and is supposed to change with respect to the independent variable.
Control variable:
Control variable includes the variables which are of no concern in the experiment and must be constant so that they do not interfere with the results of the experiment. Change in control variable might affect the results of an experiment.
In Anna's experiment, the independent variable is the atmospheric conditions. The dependent variable is cell phone reception that will change according to the atmospheric conditions. All other things related to the experiment are control variables like cellphone, location of the cell phone. Both of these must stay constant to collect the best data.
Hence, the best option is D.
Answer:
During dormancy, a tree's metabolism, energy consumption, and growth all slow down significantly in order to endure the harsh season of winter when water and sunlight are more scarce.
Explanation:
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Answer:
The total energy in the system remains the same as the decrease in chemical energy equals the increase in thermal and radiant energy
Explanation:
According to the law of conservation of energy, "energy cannot be created nor destroyed, but only transformed".
This means that for an isolated system, the total energy of the system must remain constant.
In this case, the total energy of the system (the battery and the lightbulb) is the sum of 3 components:
- Chemical energy of the battery
- Thermal energy (the heat produced by the light bulb)
- Radiant energy (the light emitted by the bulb)
The sum of these 3 components of energy must be constant.
At the beginning, all the energy is stored as chemical energy inside the battery. Later, this energy is converted into electrical energy first (when the current starts circulating through the circuit), and finally, this energy is entirely converted into thermal energy and radiant energy as heat and light emitted by the bulb.
Answer:
V = 381.70 m³
Explanation:
ρ air = 1.28 kg / m³
ρ helium = 0.18 kg / m³
R = 4.5 m
Vb = 0.068 m³
mb = 123 kg
To determine the volume of helium in the balloon when fully inflated
V = 4 / 3 π * R ³
V = 4 * π / 3 ( 4.5 m )³
V = 381.70 m³
To determine the mass total
m = ρ helium * V
m = 0.18 kg / m³ * 381.70 m³
m = 68.70 kg
mt = ( 68.70 + 123 )kg
mt = 191.70 kg
