Consider the following statements for a power shovel: (i) Output can be increased by reducing the angle of swing for a given depth of cut. (ii) For a given angle of swing, output will be maximum at optimum depth of cut. (iii) Output can be increased by keeping the depth of cut less than optimum depth. (iv) Output can be increased by increasing the size of shovel. A. (ii), (iii) and (iv) are correct B. (i), (ii) and (iv) are correct C. (i), (iii) and (iv) are correct D. (i) and (iv) are correct

The correct answer is: (i) and (iv) are correct.

Statement (i) is correct because reducing the angle of swing will increase the amount of material that can be loaded into the bucket per cycle. This is because the bucket will be able to travel further horizontally before it reaches the end of its swing.

Statement (ii) is incorrect because the optimum depth of cut is the depth at which the power shovel can move the most material in the least amount of time. If the depth of cut is too shallow, the power shovel will spend more time moving the bucket up and down than it will actually digging. If the depth of cut is too deep, the power shovel will spend more time lifting the bucket than it will actually digging.

Statement (iii) is incorrect because keeping the depth of cut less than optimum depth will actually decrease the output of the power shovel. This is because the power shovel will spend more time moving the bucket up and down than it will actually digging.

Statement (iv) is correct because increasing the size of the shovel will increase the amount of material that can be loaded into the bucket per cycle. This is because the bucket will be able to hold more material.

In conclusion, the correct answer is: (i) and (iv) are correct.