1. Mechanics
  2. 1. Units, Dimensions and Errors
    2. Vectors and Scalars
    3. Motion in a Straight Line
    4. Projectile Motion
    5. Newton's Laws of Motion
    6. Friction
    7. Work, Energy, Power and Collision
    8. Circular motion
    9. Rotational motion
    10. Simple Harmonic Motion
    11. Gravitation
    12. Elasticity
    13. Surface Tension
    14. Fluid dynamics and Viscosity
    15. Hydrostatics
  3. Heat and Thermodynamics
  4. 16. Thermometry
    17. Thermal expansion
    18. Calorimetry, Change of State and Hygrometry
    19. Gas Laws and Kinetic theory of Gases
    20. Transmission of Heat
    21. Thermodynamics
  5. Sound and Waves
  6. 22. Wave
    23. Superposition of Waves
    24. Stationary/ Standing waves
    25. Doppler's effect and Musical sound
  7. Optics
  8. 26. Reflection of Plane and Curved Mirrors
    27. Refraction at Plane surfaces and Total internal reflection
    28. Refraction through prism and Dispersion of Light
    29. Refraction through Lenses
    30. Chromatic abberation in Lenses, Optical instruments and Human eye
    31. Velocity of Light
    32. Photometry
    33. Wave nature of Light
  9. Electrostatics
  10. 34. Charge and Force
    35. Electric Field and Potential
    36. Capacitance
  11. Electrodynamics
  12. 37. Electric current
    38. Heating Effect of Current
    39. Thermoelectricity
    40. Chemical effect of Current
    41. Meters
  13. Electromagnetism
  14. 42. Properties of Magnets
    43. Magnetic effects of Current
    44. Electromagnetic induction
    45. Alternating current
  15. Modern Physics
  16. 46. Cathode rays, Positive rays and Electrons
    47. Photoelectric effect
    48. X-rays
    49. Atomic structure and Spectrum
    50. Radioactivity
    51. Nuclear physics
    52. Semiconductor and Semiconductor devices
    53. Diode and Triode valves
    54. Logic gates
    55. Relativity and Universe
    56. Particle physics
Mechanics
2. Vectors and Scalars
DIFFERENCES BETWEEN SCALAR AND VECTOR
Property
Scalar
Vector
Definition
Quantities with only magnitude
Quantities with both magnitude and direction
Direction
No direction
Has specific direction
Representation
Represented by a number and unit
Represented by an arrow with length and direction
Change
Changes only with change in magnitude
Changes with change in magnitude or direction or both
Addition
Simple arithmetic addition
Vector addition using parallelogram or triangle law
Examples
Mass, temperature, time, speed
Displacement, velocity, force, acceleration
TENSORS
Tensors are those quantity whose magnitude differs from direction to direction
Examples
  1. Pressure
  2. Stress
  3. Modulus of elasticity
  4. Moment of inertia
  5. Coefficient of Viscosity
CALCULATION OF VECTORS
Unit vector
Vector with unit magnitude is called Unit vector. It is represented by \(\hat{a}\)
1. A man goes 10 km/hr east and 20 km/hr north. Find the relative velocity.

[BP 2014, BP 2016]

  • 22.46 km/hr
  • 22.36 km/hr
  • 22.56 km/hr
  • 24.36 km/hr
2. What will be the maximum magnitude of (A - B)?

[BP 2013]

  • A + B
  • A - B
  • √(A² + B²)
  • √(A² - B²)
3. Two vectors A = 5i + 7j - 3k and B = 2i + 2j - ak are perpendicular to each other, then value of 'a' is

[BP 2009]

  • 12
  • -12
  • 8
  • -8
4. A vector of length l is turned through the angle θ about its tail. What is the change in the position vector of its head?

[BP 2009]

  • l cos θ
  • 2l sin(θ/2)
  • 2l cos(θ/2)
  • l sin θ
5. The resultant of two forces 3p and 2p is R. If the first force is doubled then the resultant is also doubled. The angle between the forces is

[IOM 2009, KU 2014, KU 2013]

  • 45°
  • 90°
  • 60°
  • 120°
6. Which of the following is a vector?

[IOM 2012]

  • Electric potential
  • Electric flux
  • Charge density
  • Electric field intensity
7. Two bodies are moving with velocities V₁ and V₂ respectively. V₁ is along X-axis and V₂ moving in the first quadrant, makes an angle θ with V₁. The relative velocity of V₁ with respect to x-component of V₂ will be

[MOE 2013]

  • V₁ - V₂ cosθ
  • V₁ - V₂ sinθ
  • V₁ cosθ - V₂
  • V₂ sinθ + V₂
8. A body A moving north with 3 km/s and B with 4 km/s east. What is the relative velocity of A with respect to B?

[MOE 2011]

  • 3 km/s west of north
  • 5 km/s east of north
  • 5 km/s towards north
  • 5 km/s towards west
9. A vector remains unchanged

[KU 2010]

  • When it is rotated by an arbitrary angle
  • When it is cross multiplied by a unit vector
  • When it is multiplied by a scalar
  • When it is slid parallel to itself
10. A body moves 30 m due north, 20 m due east and 30√2 m due southwest. The total displacement covered by the body from its initial position is

[IE 2011]

  • 14 m, southwest
  • 28 m south
  • 10 m west
  • 18 m south
11. The x-component of a vector making an angle of 30° with horizontal is 3. Its y-component is

[Bangladesh 2009]

  • 3
  • √3/2
  • 3/√2
  • √3
12. Which of the following is a scalar quantity?

[KU 2009]

  • Electric field
  • Electrostatic potential
  • Angular momentum
  • Torque
13. Two forces of magnitude F have resultant of the same magnitude F. The angle between the two forces is

[IOM 2008]

  • 45°
  • 120°
  • 150°
  • 180°
14. Three vectors are arranged to form a right-angled triangle of sides 5, 12 and 13 units. The sum of the two vectors is equal to the third. The angle between those of magnitudes 12 and 13 will be

[IOM 2005]

  • sin⁻¹(12/13)
  • cos⁻¹(12/13)
  • cos⁻¹(5/13)
  • tan⁻¹(5/13)
15. Resultant of two forces F₁ and F₂ is R and the resultant is at right angle to the force F₁. Then the force F₂ is equal to

[IOM 2002, IOM 2001]

  • 2F₁
  • 0
  • F₁
  • √2 F₁
16. Magnetic moment is
  • a scalar quantity
  • a vector quantity
  • a universal constant
  • a tensor
17. Two vectors have a sum A and a difference B. If A = B then, the angle between the two vectors is

[IOM 1997]

  • 45°
  • 120°
  • 90°
18. Which of the following is not a vector quantity?

[MOE 2063]

  • Angular momentum
  • Magnetic intensity
  • Torque
  • Energy
19. If A, B, C have magnitudes 6, 8 & 10 respectively, and A + B = C, the angle between A & B is

[MOE 2056]

  • 90°
  • 45°
  • 180°
20. Three forces of magnitudes 1N, 3N and 2N are acting at angles of 0°, 90° and 120° with +ve X-axis respectively, then the resultant will act along the:

[MOE 2054]

  • positive x-axis
  • positive y-axis
  • negative x-axis
  • negative y-axis
21. The condition for A + B = A - B is that:

[BPKIHS 2005]

  • B = 0
  • B is a unit vector
  • A = B
  • A = 0
22. The resultant of two forces 8N and 6N is
  • 1 N
  • 10 N
  • 15 N
  • 20 N
23. The resultant of two forces P and Q is perpendicular to P and is equal to P. Then the magnitude of another force Q is
  • √3 P
  • 2P
  • √2 P
24. The sum of two unit vectors is a unit vector. Then their difference will be
  • 2
  • √3
  • √2
  • Zero
25. The dot product of two vectors is 6 and their magnitudes are 4 and 3. Then angle between these vectors will be
  • 45°
  • 60°
  • 90°
26. The vector sum and vector difference of two vectors are at right angle. Then these vectors

[BP 2017]

  • must be equal
  • must have equal magnitude
  • must be perpendicular
  • must be parallel
27. The dot product of vectors is √3 times the magnitude of their cross product. Then angle between these vectors will be
  • 30°
  • 45°
  • 60°
  • 75°
28. If a = b then
  • a=b
  • a = b
  • both a and b
  • Neither a nor b
29. The angle between A and B is θ. The value of A.BxA is
  • A^2B
  • Zero
  • A^2B sin θ
  • A^2B cos θ
30. Which of the following can't be resultant of the vectors of magnitude 5 and 10?
  • 7
  • 15
  • 5
  • 2
31. What is the component of A = 2i + 3j along B = i +j?
  • 5√2
  • 5/√2
  • 10√2
  • 10/√2
32. If a = b + c and |a|=5, |b|=4, |c|=3, the angle between a and c is
  • cos ^-1 (3/5)
  • cos ^-1 (4/5)
  • (\(\pi \))/2
  • sin^-1 (3/4)
33. Which of the following is not defined in vectors?
  • addition
  • subtraction
  • division
  • multiplication
34. If |a.b|= |axb|, then |a+b|
  • a+b
  • a-b
  • √(a^2+b^2+2ab)
  • √(a^2+b^2+√2ab)
35. Which set of forces acting on a body never produces zero acceleration?

[IOM]

  • 10N, 10N, 20N
  • 6N, 8N, 10N
  • 7N, 12N, 20N
  • 1N, 2N, 3N
36. The unit vector along i + j is
  • k
  • i+j
  • (i+j)/√2
  • (i+j)/2
37. Two diagonals of a parallelogram are (2i + 2j) and (2i - 2j) cm. Then area of the parallelogram will be
  • 8 cm²
  • 4√2 cm²
  • 4 cm²
  • 2 cm²
38. What is the projection of i + 2j + 3k on i + j + k?
  • 3√2
  • 1/(2√3)
  • 13
  • 4√2
39. The length, breadth and height of a hall are 12m, 4m and 3m. What is the displacement of a fly which flies from one corner to another corner of the hall?
  • 13 m
  • 15 m
  • 17 m
  • 19 m
40. The forces F₁ = (3i + 4j) N and F₂ = (4i + 3j) N are acting on a body. The resultant force on the body is
  • 7√2 N
  • 5√2 N
  • 10 N
  • 14 N
41. Let the angle between two non-zero vectors P and Q be 120° and its resultant be R. Then

[KU 2015]

  • |R| must be equal to |P - Q|
  • |R| must be less than |P - Q|
  • |R| must be greater than |P - Q|
  • |R| may equal to |P - Q|
42. If the two vectors V and V₁ have the same magnitude, then which of the following is not true for the sum of their magnitude?

[KU 2016]

  • 0
  • 1/4 V
  • 2V
  • 4V