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True or False: Benzene undergoes electrophilic substitution reactions readily.
- True
- False
Answer: True
Benzene's delocalized π-electrons attract electrophiles. Substitution preserves aromatic stability; addition would break resonance. Nitration, halogenation, sulfonation are classic examples. [[NCERT Chemistry Class 11]]
The SI unit of magnetic flux is ________.
- Tesla
- Weber
- Henry
- Gauss
Answer: Weber
Weber (Wb) = magnetic flux; Tesla (T) = magnetic flux density (B = Φ/A). 1 Wb = 1 T·m². Important for electromagnetism problems. [[NCERT Physics Class 12]]
True or False: Viscosity of liquids decreases with increase in temperature.
- True
- False
Answer: True
Higher temperature increases molecular kinetic energy, reducing intermolecular forces and internal friction. Hence, honey flows faster when heated. Opposite trend for gases. [[NCERT Physics Class 11]]
Bt cotton contains a gene from which organism for pest resistance?
- Agrobacterium
- Bacillus thuringiensis
- Escherichia coli
- Rhizobium
Answer: Bacillus thuringiensis
Bt gene produces Cry protein toxic to bollworm larvae but safe for humans. First commercially approved GM crop in India (2002). Important for biotechnology and agriculture. [[DBT Reports, NCERT Biology Class 12]]
The inert pair effect is most prominent in the ________ group of p-block elements.
- 13
- 14
- 15
- 16
Answer: 13
In Group 13 (B, Al, Ga, In, Tl), ns² electrons resist participation in bonding down the group. Tl⁺ is more stable than Tl³⁺ due to inert pair effect. Important for periodic trends. [[NCERT Chemistry Class 11]]
The power of a lens is measured in:
- Meters
- Diopters
- Candela
- Lux
Answer: Diopters
Lens power P = 1/f (in meters), unit: diopter (D). Positive for convex, negative for concave lenses. Used in prescribing corrective eyewear. [[NCERT Physics Class 10]]
The hormone that triggers ovulation in human females is ________.
- FSH
- LH
- Estrogen
- Progesterone
Answer: LH
LH (Luteinizing Hormone) surge from pituitary triggers release of mature ovum from Graafian follicle (~day 14 of menstrual cycle). Critical for reproductive physiology. [[NCERT Biology Class 12]]
True or False: The standard hydrogen electrode (SHE) has a potential of 0 V by definition.
- True
- False
Answer: True
SHE is the reference electrode with E° = 0.00 V at 298K, 1 atm, 1M H⁺. All other electrode potentials are measured relative to SHE. Fundamental for electrochemical series. [[NCERT Chemistry Class 12]]
Which of the following is NOT a biodiversity hotspot in India?
- Western Ghats
- Eastern Himalayas
- Sundaland
- Thar Desert
Answer: Thar Desert
India has four hotspots: Himalayas, Indo-Burma, Sundaland, Western Ghats. Thar Desert, while ecologically important, isn't classified as a hotspot (requires >1,500 endemic plants and >70% habitat loss). [[MoEFCC, NCERT Biology Class 12]]
True or False: Homologous organs indicate common ancestry.
- True
- False
Answer: True
Homologous structures (e.g., human arm, bat wing, whale flipper) share similar bone structure but different functions, indicating divergent evolution from common ancestor. Key evidence for evolution. [[NCERT Biology Class 12]]
True or False: Fleming's left-hand rule is used to find the direction of induced current.
- True
- False
Answer: False
Fleming's left-hand rule: for motors (force on current-carrying conductor). Right-hand rule: for generators (induced current). Mnemonic: 'Left for Motor, Right for Generator'. [[NCERT Physics Class 10]]
Which organelle is known as the 'powerhouse of the cell'?
- Nucleus
- Ribosome
- Mitochondria
- Golgi apparatus
Answer: Mitochondria
Mitochondria generate ATP through cellular respiration (Krebs cycle, ETC). They have their own DNA and ribosomes, supporting endosymbiotic theory. Fundamental cell biology concept. [[NCERT Biology Class 11]]
True or False: Colligative properties depend on the nature of solute particles.
- True
- False
Answer: False
Colligative properties (vapor pressure lowering, boiling point elevation, etc.) depend only on number of solute particles, not their identity. Important for solution chemistry. [[NCERT Chemistry Class 12]]
Which AI technique enables computers to learn from data without explicit programming?
- Expert Systems
- Machine Learning
- Robotics
- Natural Language Processing
Answer: Machine Learning
Machine Learning algorithms identify patterns in data to make predictions/decisions. Subfields include supervised, unsupervised, reinforcement learning. Key emerging technology topic. [[NITI Aayog Reports]]
True or False: Angular momentum is conserved when net external torque is zero.
- True
- False
Answer: True
Conservation of angular momentum: if τ_ext = 0, L = constant. Explains ice-skater spin, planetary motion, gyroscopes. Fundamental rotational dynamics principle. [[NCERT Physics Class 11]]
Which sugar is present in RNA?
- Glucose
- Fructose
- Ribose
- Deoxyribose
Answer: Ribose
RNA contains ribose sugar (with -OH at 2' carbon); DNA has deoxyribose (-H at 2' carbon). This structural difference affects stability and function of nucleic acids. [[NCERT Chemistry Class 12]]
The National Air Quality Index (NAQI) in India uses ________ color codes to represent air quality levels.
- 5
- 6
- 7
- 8
Answer: 6
NAQI has six categories: Good (Green), Satisfactory (Light Green), Moderately Polluted (Yellow), Poor (Orange), Very Poor (Red), Severe (Maroon). Helps public understand pollution levels. [[CPCB Guidelines]]
True or False: A food chain always starts with herbivores.
- True
- False
Answer: False
Food chains start with producers (autotrophs like plants) that convert solar energy to chemical energy. Herbivores are primary consumers. Understanding trophic levels is fundamental. [[NCERT Biology Class 12]]
Which disease is transmitted by the female Anopheles mosquito?
- Dengue
- Malaria
- Chikungunya
- Zika
Answer: Malaria
Female Anopheles mosquito transmits Plasmodium parasites causing malaria. Dengue/Zika are spread by Aedes aegypti. Vector-borne disease knowledge is vital for health sections. [[NCERT Biology Class 12, NVBDCP Guidelines]]
A device that converts AC to DC is called a ________.
- Transformer
- Rectifier
- Inverter
- Amplifier
Answer: Rectifier
Rectifiers (using diodes) convert alternating current to direct current. Half-wave and full-wave rectifiers are basic power supply components. Essential for electronics fundamentals. [[NCERT Physics Class 12]]