Related Questions

The stiffness of a closely coiled helical spring subjected to an axial load W is equal to (where G = Modulus of rigidity and n = Number of active coils)
A $$\frac{{{\text{G}}{{\text{d}}^4}}}{{8{{\text{D}}^3}{\text{n}}}}$$
B $$\frac{{{\text{G}}{{\text{d}}^3}}}{{8{{\text{D}}^3}{\text{n}}}}$$
C $$\frac{{{\text{G}}{{\text{d}}^4}}}{{4{{\text{D}}^3}{\text{n}}}}$$
D $$\frac{{{\text{G}}{{\text{d}}^4}}}{{8{{\text{D}}^2}{\text{n}}}}$$
A close coil helical spring of mean diameter D consists of n coils of diameter d. If it carries an axial load W, the energy stored in the spring, is
A $$\frac{{4{\text{W}}{{\text{D}}^2}{\text{n}}}}{{{{\text{d}}^4}{\text{N}}}}$$
B $$\frac{{4{{\text{W}}^2}{\text{Dn}}}}{{{{\text{d}}^4}{\text{N}}}}$$
C $$\frac{{4{{\text{W}}^2}{{\text{D}}^3}{\text{n}}}}{{{{\text{d}}^4}{\text{N}}}}$$
D $$\frac{{4{{\text{W}}^2}{{\text{D}}^3}{{\text{n}}^2}}}{{{{\text{d}}^4}{\text{N}}}}$$
A helical antenna is used for satellite tracking because of
A Circular polarization
B Maneuverability
C Beamwidth
D Gain
The cracks in helical springs used in railway carriages usually start on the inner side of the coil because of the fact that
A It is subjected to a higher cyclic loading than the outer side
B It is subjected to a higher stress than the outer side
C It is more stretched than the outer side during the manufacturing process
D It has a lower curvature than the outer side
Multilayer helical windings are commonly used in the transformers as high voltage windings
A upto 20 kV
B upto 50 kV
C upto 80 kV
D for 110 kV and above
In the calculation of induced shear stress in helical springs, the Wahl's stress factor is used to take care of
A Combined effect of transverse shear stress and bending stress in the wire
B Combined effect of bending stress and curvature of the wire
C Combined effect of transverse shear stress and curvature of wire
D Combined effect of torsional shear stress and transverse shear stress in the wire
Helical windings are used in
A distribution transformers
B power transformers
C shell type transformers
D none of the above
Helical screw agitator is used for
A Mixing highly viscous pastes
B Blending immiscible liquids
C Mixing liquids at very high temperature (> 250 °C)
D None of these
Which of the following materials is used for making coils of standard resistances ?
A Copper
B Nichrome
C Platinum
D Manganin
The winding where dummy coils are used is sometimes called
A Duplex winding
B Triplex winding
C Forced winding
D None of the above

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