# Helical Spring Experiment Viva Questions

**Helical Spring Experiment Viva Questions and Answers**

*1. What is
the principle of a spring?*

Hooke's law

*2. Define
Hooke's law. *

According
to Hooke's law, within elastic limit, stress is directly proportional to
strain.

i.e., Stress/
Strain =a constant

*3. Define
strain. *

Strain = Change
in dimension /Original dimension

*4. Define
stress. *

It is the normal force acting per unit area

Stress = Restoring
force/Area

*5. What
will you do so that the load attached to the one end of the spring oscillates
in the vertical plane in order to obtain simple harmonic oscillations? *

Spring
should be suspended vertically and the amplitude of the oscillations should be
small.

*6. State
the condition under which a spring obeys Hooke's law. *

Extension
of the spring should remain within elastic limit.

*7. What are
the forces acting on the load that is attached to the spring which is
oscillating in a vertical plane? *

The forces
are weight and tension.

*8. Define
spring constant or force constant of a spring. *

F = -kx; where k is the spring constant. It is the
force required to produce unit extension on a spring.

*9. What is
the unit of force constant? *

newton /
metre (N/m)

*10. What are the conditions essential for the motion of a body to be simple harmonic?*

*11. What are the factors on which the period of vertical oscillations of a spring depend?*

*12. What is the unit of spring constant?*

^{-1}

*13. Which is more elastic-steel wire or rubber wire of the same diameter and length?*

*14. What is the spring constant in terms of load (M) and extension (e)*

^{-1}

*15. Aim of Experiment.*

To determine the spring constant by measuring the time period of vertical oscillations of a known load and to check the result by measuring the extension for a known force

*16. Apparatus
of Experiment.*

A helical
spring, Stand, Slotted weights, Stop-watch etc..

*17. Principle of Experiment.*

i. **Vertical
oscillations: **The period of vertical oscillations of a helical spring is given
by,

T = 2π√(M/K)

K = 4π^{2}(M/T^{2})

Where, K =
spring constant, M = Total mass attached, T = Period of oscillations

ii. **Load
extension method:** Using Hooke’s law, load is proportional to extension,

Spring
constsnt, K = Load/Extension = mg/l

*18. Procedure
of Vertical Oscillations of Experiment*

The given
spring is suspended from a rigid support. A weight hanger with a dead load (w_{0})
is suspended at the lower end of the spring (w_{0} should be sufficient
to bring the spring in the elastic mood). A pointer is attached to the spring.
The weight is slightly pulled down and released. The spring executes vertical
oscillations. The time taken for 20 oscillations is noted and the period of
oscillation (t/20) is calculated. Changing the loads [say (w_{0}+w), (w_{0}+2w),…..]
and the period of oscillations are again determined. In each case M/T_{2}
is calculated and hence its mean value is determined. A graph is plotted with M
along the X-axis and T_{2} along, the Y-axis. The graph is found to be
a straight line. From this K can also be calculated.

*19. Procedure
of Load-extension method of Experiment*

The given
spring is suspended from a rigid support. A pointer attached to the spring
moves over a scale. Reading on the scale for w0, (w_{0}+w), (w_{0}+2w)….
are found. The mean value of scale reading for loading and unloading are r_{0},
r_{1}, r_{2} ….. respectively. Extension (l) for loads w, 2w, 3w
…. Are given by (r_{1}-r_{0}), (r_{2}-r_{0}), (r_{3}-r_{0})
etc. are calculated. The spring constant,

K = Load/
Extension

A graph is
plotted with M along the X-axis and extension along the Y-axis. The graph is
found to be a straight line. From this K can also be calculated.

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