搜题请搜索小程序“爱下问搜题”
问题 选择题

图中电阻R1、R2、R3的阻值相等，电池的内阻不计．开关K接通后流过R2的电流是K 接通前的（　　）

A．

1
2

B．

2
3

C．

1
3

D．

1
4

答案

K接通前，R1、R2串联，I2=

E
2R
．

K接通后，由并联电路的规律可知I′2=

E
R+0.5R
×
1
2
=
E
3R

故

I2′
I2
=
2
3
；

故选B．

单项选择题

In analyzing disclosures related to the financing liabilities of a company, which of the following disclosures would be least helpful to the analyst()

A. The interest expense for the period as provided on the income statement or in a footnote.

B. The present value of the future bond payments discounted at the coupon rate of the bonds.

C. Fillings with the Securities and Exchange Commission (SEC) that disclose all outstanding securities and their features.
查看答案
单项选择题

反复性过劳损伤的初期治疗方法不包括（）

A.全身有氧调节

B.经皮电神经刺激

C.类鸦片镇痛剂

D.冰按摩

E.避免反复活动
查看答案