初级水电工实际常识试题(他人的)(国外英文资料).doc

初级水电工理论知识试题(别人的)(国外英文资料) One, single item choice (20 points, 1 point per question) Two resistors, when they are connected in parallel, the power ratio of the two resistors, if they are in series, the power ratio of the two resistors will be. A, 4:3 B, 9:16 C, 16:9 An electric current of resistance R is applied to an electric current of 220V. A, 220 over n B, 220 over nR C, 220 over R D, 220R/n The main reason for the induction of electromotive force in the coil is. There is no change in the number of magnetic lines in the coils through B and through the coils C, whether the coil is closed, or whether the coil has a magnetic pass The wire is in the magnetic field. A, the force of A magnetic field force B, only if it is parallel to the direction of the magnetic field C, as long as it is not parallel to the magnetic field direction, can be affected by the force of the magnetic field The third element of sine is. A, maximum, angular frequency, initial phase B, period, frequency, and angular frequency C, maximum, valid value, frequency D, maximum, period, frequency A fluorescent lamp load, to improve power factor, should be in. A, the load is parallel capacitor B, the series capacitor C in the load, the series inductance in the load Three-phase symmetrical load, when it got behind star, meet online on the three-phase power supply voltage of 380 v or twine triangle in line voltage is 220 v three-phase power supply, in both cases, the power input power will be. A is equal to B, 3 times C, so D, 8. Three phase symmetry ac load, the use of star connection to the phase voltage is 220 v power supply, the known, the load current is 10. A, the power factor is 0.8, the total power of the circuit. A, 5280 B, 3048 C, 1760 Using a multimeter resistor, the diode is forward resistance and reverse resistance, and if the amount of resistance of the two measurements is very large, it is indicated. A, the one-way conduction of the pipe is good, and the PN junction of the pipe has been pu