Assertion (A): | Elastomers are used as vibration dampers. |
Reason (R): | Elastomers show elastic hysteresis. |
1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
3. | (A) is true but (R) is false. |
4. | Both (A) and (R) are false. |
Assertion (A): | The bridges are declared unsafe after long use. |
Reason (R): | The bridges lose their elastic strength with time. |
1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
3. | (A) is true but (R) is false. |
4. | Both (A) and (R) are false. |
A rod of length l and negligible mass is suspended at its two ends by two wires of steel (wire A) and aluminium (wire B) of equal lengths (figure). The cross-sectional areas of wires A and B are respectively. ()
a. | Mass m should be suspended close to wire A to have equal stresses in both wires. |
b. | Mass m should be suspended close to B to have equal stresses in both wires. |
c. | Mass m should be suspended in the middle of the wires to have equal stresses in both wires. |
d. | Mass m should be suspended close to wire A to have equal strain in both wires. |
The correct statements are:
1. (b, c)
2. (a, d)
3. (b, d)
4. (c, d)