Which of the following statements are incorrect?
(i) A bag placed below the seat of a moving bus is in motion with respect to the floor of the bus.
(ii) While measuring length of an object using a metre scale, use the zero-mark even if the ends are worn out.
(iii) Blinking of eyes is an example of periodic motion.
(iv) If a body as a whole moves around in a circular path, the motion is known as revolution

Options

A. (i), (ii) and (iv) only
B. (i), (ii) and (iii) only
C. (ii), (iii) and (iv) only
D. (i), (iii) and (iv) only

Explanation

To determine which statements are incorrect, we will analyze each statement one by one.

**Step 1: Analyze Statement (i)**
- Statement: "A bag placed below the seat of a moving bus is in motion with respect to the floor of the bus."
- Analysis: The bag is inside the bus and moves along with it. Therefore, with respect to the floor of the bus, the bag is at rest. This statement is incorrect.

**Step 2: Analyze Statement (ii)**
- Statement: "While measuring the length of an object using a metre scale, use the zero-mark even if the ends are worn out."
- Analysis: If the ends of the metre scale are worn out, the zero-mark may not be accurate. Using the zero-mark in this case would lead to measurement errors. This statement is also incorrect.

**Step 3: Analyze Statement (iii)**
- Statement: "Blinking of eyes is an example of periodic motion."
- Analysis: Periodic motion is defined as motion that repeats at regular intervals. Blinking is not consistent and can vary from person to person, making it a random motion rather than a periodic one. This statement is incorrect.

**Step 4: Analyze Statement (iv)**
- Statement: "If a body as a whole moves around in a circular path, the motion is known as revolution."
- Analysis: This statement is correct. When an object moves in a circular path around a fixed point, it is indeed described as revolution.

**Conclusion:**
The incorrect statements are (i), (ii), and (iii).

**Final Answer:**
The incorrect statements are:
- (i) A bag placed below the seat of a moving bus is in motion with respect to the floor of the bus.
- (ii) While measuring length of an object using a metre scale, use the zero-mark even if the ends are worn out.
- (iii) Blinking of eyes is an example of periodic motion.

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