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Generate QuizSpace – Hard Level – GK Questions
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Shapiro delay measures general relativistic time dilation of signals passing near massive bodies.
- True - confirmed by Cassini/radar ranging
- False - Newtonian effect
- True - only for light not radio
- False - disproven by LIGO
Answer: True - confirmed by Cassini/radar ranging
Signals traversing curved spacetime experience extra delay proportional to gravitational potential; Cassini solar conjunction test verified GR to 10⁻⁵ precision.
Solar sails propel spacecraft using momentum transfer from reflected photons, achieving continuous acceleration without propellant.
- True - demonstrated by IKAROS/LightSail
- False - theoretical only
- True - but requires laser beaming
- False - violates conservation laws
Answer: True - demonstrated by IKAROS/LightSail
IKAROS (2010) and LightSail-2 (2019) validated photon pressure propulsion; enables indefinite missions limited only by sail degradation/orbital mechanics.
Pair-instability supernovae occur in very massive stars (140-260 solar masses) where gamma rays create electron-positron pairs reducing _______.
- Opacity
- Radiation pressure support
- Nuclear fuel
- Rotation rate
Answer: Radiation pressure support
Pair production reduces photon pressure triggering catastrophic core contraction/explosion completely disrupting star; leaves no remnant unlike core-collapse SN.
Auroral emissions on Jupiter are primarily driven by _______ rather than solar wind interaction.
- Volcanic plasma from Io
- Internal magnetic reconnection
- Cosmic ray bombardment
- Ring particle charging
Answer: Volcanic plasma from Io
Io's volcanic SO₂ ionizes forming plasma torus; corotation enforcement currents accelerate electrons precipitating into polar atmosphere generating persistent aurorae.
Transmission spectroscopy during planetary transits reveals atmospheric composition by analyzing wavelength-dependent _______.
- Emission lines
- Absorption depth variations
- Polarization
- Phase curves
Answer: Absorption depth variations
Atmospheric species absorb specific wavelengths increasing effective planet size; JWST transmission spectra detect H₂O/CO₂/CH₄ in exoplanet atmospheres.
ISRO's RLV-TD HEX-01 test in 2016 validated hypersonic flight characteristics at Mach _______.
- 3
- 5
- 8
- 10
Answer: 5
HEX-01 reached Mach ~5 during re-entry from 65 km altitude, testing aero-thermodynamics/navigation/control for reusable launch vehicle concept.
Helioseismology probes solar interior structure by analyzing oscillation modes of the photosphere.
- True - reveals convection zone depth/radiative zone rotation
- False - only studies surface
- True - but only for flares
- False - requires spacecraft
Answer: True - reveals convection zone depth/radiative zone rotation
p-mode/g-mode frequencies constrain internal sound speed profile, revealing tachocline location and differential rotation; validated solar models.
Voyager 2 is the only spacecraft to have visited Uranus and Neptune.
- True - flew by both in 1986/1989
- False - Voyager 1 also visited
- True - but New Horizons visited Neptune
- False - no spacecraft visited Uranus
Answer: True - flew by both in 1986/1989
Voyager 2 conducted Uranus flyby Jan 1986 and Neptune flyby Aug 1989; no subsequent missions have visited ice giants, leaving major knowledge gaps.
Kilonovae are electromagnetic counterparts to neutron star mergers producing heavy elements via _______.
- Silicon burning
- R-process nucleosynthesis
- Proton-proton chain
- Triple-alpha process
Answer: R-process nucleosynthesis
GW170817 kilonova confirmed r-process production of gold/platinum/lanthanides in neutron-rich ejecta, resolving origin of half elements heavier than iron.
The Hera mission will study the aftermath of DART's impact on Dimorphos to measure _______.
- Composition change
- Momentum transfer efficiency
- Orbital period shift
- Surface albedo
Answer: Momentum transfer efficiency
Hera (ESA, launch 2024) will characterize crater morphology and momentum enhancement factor β, calibrating kinetic impact models for planetary defense.
Galaxy rotation curves remain flat at large radii instead of declining Keplerian, providing evidence for _______.
- Modified gravity
- Dark matter halos
- Stellar population gradients
- Gas pressure support
Answer: Dark matter halos
Flat rotation curves imply enclosed mass increases linearly with radius beyond visible disk, requiring extended dark matter halo dominating gravitational potential.
Aerocapture uses atmospheric drag to insert spacecraft into orbit around a planet in a single pass, unlike aerobraking which requires multiple passes.
- True - saves significant propellant
- False - synonymous terms
- True - but only for Earth
- False - never successfully demonstrated
Answer: True - saves significant propellant
Aerocapture achieves orbit insertion in one atmospheric pass requiring precise guidance; aerobraking gradually lowers apoapsis over weeks/months. Aerocapture remains unflown but studied for Mars/Venus/Titan.
Hot Jupiters are gas giants orbiting very close to host stars; they likely formed beyond snow line and migrated inward via _______.
- Disk migration or tidal interactions
- Core accretion in situ
- Gravitational instability
- Stellar capture
Answer: Disk migration or tidal interactions
Type I/II disk migration or high-eccentricity tidal circularization explains hot Jupiter presence interior to snow line where gas giant formation is unlikely.
New Horizons' flyby of Arrokoth revealed it to be a contact binary formed by _______.
- Collisional fragmentation
- Gentle accretion in primordial disk
- Tidal disruption
- Volcanic resurfacing
Answer: Gentle accretion in primordial disk
Arrokoth's bilobate shape with aligned lobes indicates low-speed merger of two planetesimals in cold classical Kuiper Belt, preserving early solar system conditions.
The reionization epoch occurred approximately between which redshift ranges?
- z=100-50
- z=20-6
- z=3-1
- z=0.5-0
Answer: z=20-6
First stars/galaxies ionized neutral hydrogen between z~20-6 (~180 Myr-1 Gyr post-Big Bang), ending cosmic dark ages; confirmed by CMB polarization and quasar spectra.
Nuclear thermal propulsion (NTP) achieves higher specific impulse than chemical rockets by heating propellant via _______.
- Electric arc
- Nuclear fission reactor
- Radioactive decay
- Fusion plasma
Answer: Nuclear fission reactor
NTP uses fission reactors to heat liquid hydrogen to ~2500 K, achieving Isp ~900 s vs ~450 s for LH2/LOX chemical engines, enabling faster Mars transit.
The Test Vehicle Abort Mission-1 (TV-D1) for Gaganyaan successfully demonstrated crew escape at what altitude?
- 5 km
- 11.7 km
- 17 km
- 30 km
Answer: 17 km
TV-D1 conducted on Oct 21, 2023, separated the Crew Escape System at ~17 km altitude during ascent, validating abort sequence and parachute recovery systems.
Frame-dragging (Lense-Thirring effect) was confirmed by which satellite experiment?
- Gravity Probe B
- LAGEOS
- MICROSCOPE
- GOCE
Answer: Gravity Probe B
Gravity Probe B (2004-2011) measured frame-dragging via gyroscope precession, confirming general relativity prediction within ~20% accuracy.
Jupiter's magnetosphere is primarily powered by which energy source?
- Solar wind
- Planetary rotation
- Tidal heating
- Internal heat
Answer: Planetary rotation
Jupiter's rapid rotation (9.9 hr) drives magnetospheric dynamics via centrifugal forces and Io plasma torus coupling, unlike solar-wind-dominated Earth.
The Sachs-Wolfe effect describes CMB temperature fluctuations caused by which phenomenon?
- Doppler shift
- Gravitational redshift/blueshift
- Thomson scattering
- Synchrotron emission
Answer: Gravitational redshift/blueshift
Photons climbing out of potential wells lose energy (redshift); falling in gain energy (blueshift), imprinting primordial density perturbations on CMB.