Answer:
<u>B. the stars of spectral type A and F are considered reasonably to have habitable planets but much less likely to have planets with complex plant - or animal - like life.</u>
Explanation:
The appropriate spectral range for habitable stars is considered to be "late F" or "G", to "mid-K" or even late "A". <em>This corresponds to temperatures of a little more than 7,000 K down to a little less than 4,000 K</em> (6,700 °C to 3,700 °C); the Sun, a G2 star at 5,777 K, is well within these bounds. "Middle-class" stars (late A, late F, G , mid K )of this sort have a number of characteristics considered important to planetary habitability:
• They live at least a few billion years, allowing life a chance to evolve. <em>More luminous main-sequence stars of the "O", "B", and "A" classes usually live less than a billion years and in exceptional cases less than 10 million.</em>
• They emit enough high-frequency ultraviolet radiation to trigger important atmospheric dynamics such as ozone formation, but not so much that ionisation destroys incipient life.
• They emit sufficient radiation at wavelengths conducive to photosynthesis.
• Liquid water may exist on the surface of planets orbiting them at a distance that does not induce tidal locking.
<u><em>Thus , the stars of spectral type A and F are considered reasonably to have habitable planets but much less likely to have planets with complex plant - or animak - like life.</em></u>
Answer:
When a circuit breaker regularly trips or a fuse repeatedly blows, it is a sign that you are making excessive demands on the circuit and need to move some appliances and devices to other circuits. Or, it may indicate that your house has too few circuits and is in need of a service upgrade.
Burning of gases is one the example of chemical change
Answer:
(a) 0.261 rad/s
(b) 1007.72 m
Explanation:
The angular velocity of the Ferris wheel is 150.0 revolutions per hour.
(a) To calculate the angular velocity of the wheel in units of radians per second, you take into account the following equivalence:
1 hour = 3600 seconds
1 revolution = 2π radians
You use the previous conversion factors:
In units of radians per seconds the wheel turns at 0.261 rad/s
(b) To find the arc length described by the wheel, you first calculate the angle described by the wheel in the time t, by using the following formula:
(1)
ω: angular velocity = 0.261 rad/s
t: time = 4.95 min
You first convert the time to units of seconds
Next, you replace the values of the parameters in the equation (1):
Next, you use the following formula for the arc length:
(2)
r: radius of the wheel = 13.0 m
You replace the values of the parameters in the equation (2):
The arc length described by the wheel is 1007.72m
Answer:
current I1 = current I2
Explanation:
since the wire is made up of the same material, from Kirchoff's current law sum of currents entering a particular node or segment of wire is equals to the sum of currents leaving that particular node or segment of wire
