如图所示，电源电动势为E，内阻忽略不计，滑动变阻器的滑片P置于中点；两平行极板间有垂直纸面的匀强磁场，一带正电的粒子以速度v₀正好水平向右匀速穿过两板（不计重力）。以下说法正确的是

A．若粒子带负电，也可以沿图示方向以相同速度沿直线穿过此区域

B．将滑片P向上移动一点，该粒子穿出两板过程中电势能减小

C．将滑片P向上移动一点，该粒子穿出两板过程中动能减小

D．把R调为原来的一半，则能沿直线穿出的粒子速度为v₀/2

A company has the following data associated with it: A target capital structure of 10% preferred stock, 50% common equity and 40% debt. Outstanding 20-year annual pay 6% coupon bonds selling for $894. Common stock selling for $45 per share that is expected to grow at 8% and expected to pay a $2 dividend one year from today. Their $100 par preferred stock currently sells for $90 and is earning 5%. The company’s tax rate is 40%. What is the after tax cost of debt capital and after tax cost of preferred stock capital Debt Capital Preferred Stock Capital（）①A. 4.2% 6.3% ②B. 4.5% 5.6% ③C. 4.2% 5.6%

A. ①

B. ②

C. ③