砂轮 1—300×50×75—A 60 L 5 V—35m/s，表示磨料代号的是（ ）。
A: A
B: 60
C: L
D: V
A: A
B: 60
C: L
D: V
举一反三
- 中国大学MOOC: 某砂轮的特性参数为P 300×30×75 A 60 L 5 B 35，其中P表示（ ）。
- 某砂轮的特性参数为P 300×30×75 A 60 L 5 B 35，其中P表示（ ）。 A: A．杯形砂轮 B: B． 平形砂轮 C: C．筒形砂轮 D: D. 碟形砂轮
- 在A+2B=3C+4D反应中，表示反应速率最快的数据是 A: v(A)=0.5mol/(L·s) B: v(B)=0.5mol/(L·s) C: v(C)=0.8mol/(L·s) D: v(D)=1.0mol/(L·s)
- A signal s(t)=3cos(20pt) (V) is quantized by a uniform quantizer, the step size of the quantizer is 0.1(V), then the minimal number of quantization level is L , the number of bits per sample is at least R , and the variance of the quantization error is T ([img=22x22]1803a28ec2869ac.png[/img]). A: L=60, R=5, T=0.000833 B: L=30, R=5, T=0.000833 C: L=60, R=5, T=0.001667 D: L=60, R=6, T=0.000833
- A signal s(t)=3cos(20pt) (V) is quantized by a uniform quantizer, the step size of the quantizer is 0.1(V), then the minimal number of quantization level is L , the number of bits per sample is at least R , and the variance of the quantization error is T ([img=22x22]1802e166a76be1c.png[/img]). A: L=60, R=5, T=0.000833 B: L=30, R=5, T=0.000833 C: L=60, R=5, T=0.001667 D: L=60, R=6, T=0.000833