objective physics

1.  ​What is the S.I. unit of electric current? (A) Volt (B) Ampere (C) Ohm (D) Watt Answer: (B) Ampere
2. ​Which mirror is used by dentists to view an enlarged image of teeth? (A) Convex mirror (B) Plane mirror (C) Concave mirror (D) Cylindrical mirror Answer: (C) Concave mirror
3. ​The focal length of a spherical mirror with a radius of curvature of 40 cm is: (A) 20 cm (B) 40 cm (C) 80 cm (D) 10 cm Answer: (A) 20 cm
4. ​The least distance of distinct vision for a normal human eye is: (A) 25 m (B) 2.5 cm (C) 25 cm (D) Infinity Answer: (C) 25 cm
5. ​Which instrument is used to measure potential difference across a circuit? (A) Ammeter (B) Voltmeter (C) Galvanometer (D) Rheostat Answer: (B) Voltmeter
6. ​The splitting of white light into its seven component colors by a glass prism is called: (A) Reflection (B) Refraction (C) Dispersion (D) Scattering Answer: (C) Dispersion
7. ​A concave lens always forms an image that is: (A) Real and inverted (B) Virtual and erect (C) Real and magnified (D) Virtual and inverted Answer: (B) Virtual and erect
8. ​The S.I. unit of power of a lens is: (A) Meter (B) Watt (C) Diopter (D) Joule Answer: (C) Diopter
9. ​The resistance of a conductor is inversely proportional to its: (A) Length (B) Area of cross-section (C) Temperature (D) Resistivity Answer: (B) Area of cross-section
10. ​A person unable to see nearby objects clearly suffers from: (A) Myopia (B) Hypermetropia (C) Presbyopia (D) Cataract Answer: (B) Hypermetropia
11. ​The commercial unit of electrical energy (1 kWh) is equal to: (A) 3.6 x 10^6 J (B) 3.6 x 10^5 J (C) 1000 J (D) 360 J Answer: (A) 3.6 x 10^6 J
12. ​The magnetic field lines inside a current-carrying straight solenoid are: (A) Circular (B) Parabolic (C) Parallel straight lines (D) Spiral Answer: (C) Parallel straight lines
13. ​A device that converts mechanical energy into electrical energy is called a: (A) Electric motor (B) Electric generator (C) Transformer (D) Galvanometer Answer: (B) Electric generator
14. ​According to Fleming's Left-Hand Rule, the forefinger points in the direction of: (A) Electric current (B) Magnetic field (C) Force on the conductor (D) Motion of the conductor Answer: (B) Magnetic field
15. ​The blue color of the sky is primarily due to: (A) Reflection of light (B) Refraction of light (C) Scattering of light (D) Total internal reflection Answer: (C) Scattering of light