Solar Physics Quiz

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What is the value of the Sun's power output, known as solar luminosity?

$3.8416 × 10^{33} W$ (correct)
$2.998 × 10^{30} W$
$5.123 × 10^{34} W$
$4.274 × 10^{12} W$

How does the solar luminosity vary over time?

It decreases linearly over millennia.
It fluctuates significantly every year.
It varies by roughly ±1 part in 1000 on 10−12 year cycles. (correct)
It remains constant with no fluctuations.

What is the estimated rate of mass conversion to energy in the Sun's core?

$5.674 × 10^{11} kg/s$
$3.8416 × 10^{33} J$s$
$2.345 × 10^{12} J$s$
$4.274 × 10^{12} kg/s$ (correct)

What causes difficulties in measuring the angular radius of the Sun from the ground?

The phenomenon of 'seeing'. (D) Signup and view all the answers

What is the uncertainty in the solar radius due to ground-based measurements?

700 km (A) Signup and view all the answers

What approximate angular radius does the Sun have, comparable to the Moon's?

960 arc sec (B) Signup and view all the answers

During its lifetime, by how much has the mass of the Sun reduced due to nuclear processing?

A few parts in 104 (D) Signup and view all the answers

What is a significant contributor to the ratio of solar luminosity used in calculating the internal structure of the Sun?

The ratio of solar luminosity to solar output (D) Signup and view all the answers

What does the term 'oblateness' refer to in the context of the Sun?

The deviation from a perfect sphere (A) Signup and view all the answers

How is the precision of the solar radius achieved according to the study?

By reducing the noise in individual pie slices (C) Signup and view all the answers

What role does centrifugal force play in the shape of the Sun?

It counteracts the inward force due to gravity (D) Signup and view all the answers

What is the significance of measuring rotational periods from Doppler shifts?

It reveals the solar rotational velocity at different latitudes (B) Signup and view all the answers

What is the implication of having a finite oblateness in the solar figure?

The Sun experiences rotation (A) Signup and view all the answers

What value was indicated for the solar oblateness in the observations from 1996–1997?

(7.77 ± 0.66) × 10−6 (D) Signup and view all the answers

What is the expected result of the Sun's figure in the absence of rotation?

An equi-potential surface with symmetry (C) Signup and view all the answers

What formula represents the net gravitational acceleration at colatitude in the presence of rotation?

$g(θ) = g_0 - R^2 ω^2 / sin^2(θ)$ (D) Signup and view all the answers

What is the significance of the Astronomical Unit (AU) in understanding solar system distances?

It allows distances of planets to be measured in terms of the average distance of the Earth's orbit. (D) Signup and view all the answers

How was the first radar reflection measurement of distance in the solar system performed?

Using reflections from Venus. (D) Signup and view all the answers

What does the International Astronomical Union define the AU to be?

It equals 149,597,870.691 kilometers. (B) Signup and view all the answers

In what conditions can radar reflections be used to determine distances in the solar system?

In favorable conditions with a clear line of sight. (D) Signup and view all the answers

How does Kepler's third law relate to the measurement of distances in AU?

It helps describe the relationship between the periods of orbits and the AU distance. (C) Signup and view all the answers

What is the fastest rotation rate observed at equatorial latitudes near the Sun's surface?

470 km/s (B) Signup and view all the answers

Which rotational frequency range is consistent with the analysis of the Sun's oblateness?

398–430 (A) Signup and view all the answers

How does the rotation of the Sun vary with latitude?

It decreases toward the poles (A) Signup and view all the answers

What is suggested about the inner regions of the Sun based on helioseismological data?

They rotate independently at varying rates (D) Signup and view all the answers

The critical frequency for solar oscillations can be formulated using which axis?

Sun's radius and mass (C) Signup and view all the answers

How is the critical period in the gravity field of the Sun expressed mathematically?

$T = 2π√{(R/g)}$ (C) Signup and view all the answers

What impact does the Sun's oblateness have on our understanding of its rotation?

It supports the idea of varying rotational rates (B) Signup and view all the answers

What is the mass ratio of the Earth to the Sun when using multiple satellites?

1/332,946 (C) Signup and view all the answers

What error does the use of RADCAT data alone lead to in the mass ratio?

1 part in 30,000 (A) Signup and view all the answers

What is the combined product of the gravitational constant and the mass of the Sun?

1.327124 × 10^26 m^3 s^−2 (D) Signup and view all the answers

To extract a value for the mass of the Sun, which value is divided into the combined product?

Gravitational constant (D) Signup and view all the answers

What is the precision of the gravitational constant known to?

1 part in 10,000 (C) Signup and view all the answers

What is the mean solar irradiance value measured from SOHO?

1366 W m^−2 (B) Signup and view all the answers

What is the variation level in solar irradiance observed during a sunspot cycle?

0.1% (C) Signup and view all the answers

What is the numerical estimate of the mass of the Sun, reliable to 1 part in 10,000?

1.9884 × 10^30 kg (B) Signup and view all the answers

What is the significance of the semi-major axis in the context of an artificial satellite's orbit around the Earth?

It relates to the satellite's altitude above the Earth's surface. (A) Signup and view all the answers

Which of the following values is crucial for calculating the semi-major axis of RADCAT?

The equatorial radius of the Earth (B) Signup and view all the answers

What is the period of the RADCAT satellite in terms of revolutions per day?

15.24243084 times per day (C) Signup and view all the answers

How is the mass of an artificial satellite treated in the calculations for orbits around the Earth?

It is neglected in comparison to the mass of the Earth. (D) Signup and view all the answers

With a mean altitude of 493 km, what is the calculated semi-major axis for RADCAT?

6871.137 km (B) Signup and view all the answers

What does the result of 21,771.924 for RADCAT represent in the orbital equation?

The ratio of the semi-major axis to the Earth's radius (B) Signup and view all the answers

What is the formula used to derive the relation between the period and semi-major axis of an object in orbit?

$T^2 ext{ ∝ } r^3$ (D) Signup and view all the answers

What is the significance of the altitude of the perigee and apogee for RADCAT?

They provide the variation in the satellite's orbit. (A) Signup and view all the answers

What is an Astronomical Unit (AU)?

The semi-major axis of Earth's orbit around the Sun. It's used as a standard unit of distance in the solar system.

How does Kepler's Third Law relate to the AU?

Kepler's Third Law helps establish the scale of the solar system. By knowing a planet's orbital period, we can calculate its distance from the Sun in AU.

How is the AU measured using radar?

Radar reflections allow us to measure the precise distance to objects in the solar system, including the AU.

What's the precise value of an AU?

The AU is defined as the average distance between the Earth and the Sun, currently set at 149,597,870.691 kilometers.