Page 46 - Physics - XI

COMPETENCY-BASED QUESTIONS
COMPETENCY-BASED QUESTIONS

Multiple Choice Questions

Q1. Which of the following is a scalar quantity?
a. Acceleration b. Electric Field c. Work d. Displacement

Q2. How many minimum number of coplanar vectors having diff erent magnitudes can be added
to give zero resultant?
a. 2 b. 3 c. 4 d. 5

Q3. Parallelogram law of vectors is applicable to the addition of
a. any two vectors
b. two scalars

c. a vector and a scalar
d. two vectors representing the same physical quantity
Q4. Which of the following is a vector quantity?

a. Acceleration b. Distance c. Speed d. Work

Q5. Two forces of 5 N each are acting on a point mass. If the angle between the forces is 60°, then
the net force acting on the point mass has a magnitude of
a. 10 N b. 53 N c. 52 N d. 2.5 N

Answer key

1. (c), 2. (b), 3. (d), 4. (a), 5. (b)

Case Study-Based Questions

Read the paragraph and answer the questions that follow.

If two vectors are acting simultaneously at a point, then it can be represented both in magnitude and
direction by the adjacent sides drawn from a point. Therefore, the resultant vector is completely
represented both in direction and magnitude by the diagonal of the parallelogram passing through the
→
→
point. If we consider two adjacent vectors P and Q having angle θ between them, and the resultant
→ →
vector is R which makes an angle of φ with the P as shown below.
D B

→ →
Q R
θ φ θ
O → A C
P
Formula for Magnitude of resultant R:

→
|R| = (P 2 +Q 2 +2PQ cos)θ

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