In an AC circuit, magnetic reversal due to phase difference between current and voltage occurs 50 or 60 times per second. A capacitor helps to improve the power factor by relieving the supply line of the reactive power.

Answer: B) Eleven Explanation: List of fundamental duties of the citizens of India in Article 51A of the Indian Constitution : 1. to abide by the constitution and respect its ideal and institutions; 2. to cherish and follow the noble ideals which inspired our national struggle for freedom; 3. to uphold and protect the sovereignty, unity and integrity of India; 4. to defend the country and render national service when called upon to do so; 5. to promote harmony and the spirit of common brotherhood amongst all the people of India   transcending religious, linguistic and regional diversities, to renounce practices derogatory to the   dignity of women; 6. to value and preserve the rich heritage of our composite culture; 7. to protect and improve the natural environment including forests, lakes, rivers, and wild-life       and to have compassion for living creatures; 8. to develop the scientific temper, humanism and the spirit of inquiry and reform; 9. to safeguard public property and to abjure violence; 10. to strive towards excellence in all spheres of individual and collective activity 11. who is a parent or guardian , to provide opportunities for education to his child, or as the case may be, ward between the age of six and fourteen years.