【单选题】
测量电流时,万用表的接线方法与直流电流表一样，应把万用表___在电路中。测量直流电压时，应把万用表与被测电路并联。
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相关试题
【单选题】
串联电路中各电阻两端电压的关系是___。
A. 各电阻两端电压相等
B. 阻值越小两端电压越高
C. 阻值越大两端电压越高
【单选题】
确定正弦量的三要素为 ___。
A. 相位、初相位、相位差
B. 最大值、频率、初相角
C. 周期、频率、角频率
【单选题】
当电压为5V时,导体的电阻值为5欧,那么当电阻两端电压为2V时,电阻值为___欧。
【单选题】
对称负载接成星形时,三相总电流___。
A. 等于零
B. 等于其中一相电流的三倍
C. 等于其中一相电流。
【单选题】
一段有源支路如图1所示，AB两端的电压UAB为___。
A. 10 V
B. —2V
C. 2V
D. —10V
【单选题】
如图2电路中，等效电阻=___
A. 150Ω
B. 900Ω
C. 600Ω
D. 100Ω
【单选题】
电流表的读数是4A，则电路中电流表的读数是 ___
【单选题】
在R、L、C串联电路中，已知＝3Ω，＝5Ω，＝8Ω，则电路的性质为 ___。
A. 感性
B. 容性
C. 阻性
D. 不能确定
【单选题】
工业生产中大量的设备均为感性负载，功率因数往往很低，常采取___的方法来提高电网的功率因数。
A. 并联电容
B. 串联电容
C. 串联电感
D. 并联电感
【单选题】
交流电压表及电流表指示的数值是___
A. 平均值
B. 有效值
C. 最大值
D. 瞬时值
【单选题】
RLC串联电路发生谐振，，R=10Ω，Ω，则谐振时的感抗为___
A. 10Ω
B. 40Ω
C. 20Ω
D. 30Ω
【单选题】
RL从电路获得最大功率，此时RL=___。
【单选题】
使用电解电容时___。
A. 负极接高电位，正极接低电位
B. 正极接高电位，负极接低电位
C. 正极接高电位，负极也可以接高电位
D. 不分正负极
【单选题】
开关接1时，电压表的读数为___。
A. 0V
B. 0.2V
C. 1.96V
D. 2V
【单选题】
开关接2时，电流表的电流为___。
A. 0A
B. 10A
C. 0.2A
D. 约等于0.2A
【单选题】
开关接1时，电流表中流过的短路电流为___。
A. 0A
B. 0.2A
C. 10A
D. 约等于0.2A
【单选题】
正弦交流电常用的表达方法有___。
A. 解析式表示法
B. 波形图表示法
C. 相量表示法
D. 以上都是
【单选题】
电感两端的电压相位超前电流___。
A. 90°
B. 180°
C. 360°
D. 30°
【单选题】
电容两端的电压相位滞后电流___。
A. 30°
B. 90°
C. 180°
D. 360°
【单选题】
应用戴维南定理求含源二端网络的输入等效电阻是将网络内各电动势___
【单选题】
LC 选频振荡电路，当电路频率等于谐振频率时，电路性质为___。
A. 电阻性
B. 感性
C. 容性
D. 纯电容性
【单选题】
阻值为4Ω的电阻和容抗为3Ω的电容串联，总复数阻抗为___
A. 3+j4
B. 3-j4
C. 4+j3
D. 4-j3
【单选题】
电动势为10V，内阻为2Ω的电压源变换成电流源时，电流源的电流和内阻是___
A. 10A，2Ω
B. 20A，2Ω
C. 5A，2Ω
D. 2A，5Ω
【单选题】
电流为5A，内阻为2Ω的电流源变换成一个电压源时，电压源的电动势和内阻为___
A. 10V，2Ω
B. 2.5V，2Ω
C. 0.4V，2Ω
D. 4V，2Ω
【单选题】
额定电压都为220V的40W、60W、100W三灯泡串联在220V的电源中，它们的发热量由大到小排列为___
A. 100W 60W 40W
B. 40W 60W 100W
C. 100W 40W 60W
D. 60W 100W 40W
【单选题】
在正弦交流电的解析式i=ImSin(ωt +φ)中，φ表示___
A. 频率
B. 相位
C. 初相位
D. 相位差
【单选题】
正弦交流电压u=100Sin(628t + 600)V，它的最大值为___。
A. 100 V
B. 100 V
C. 60V
D. 628 V
【单选题】
能表示容性电路电压与电流关系的相量图是___。
【单选题】
电路中___定律指出：流入任意一节点的电流必定等于流出该节点的电流。
A. 欧姆
B. 基尔霍夫电流
C. 楞次
D. 基尔霍夫电压
【单选题】
已知电源电压为12 V ,四只相同灯泡的工作电压都是6 V，要使灯泡都能正常工作，则灯泡应___
A. 全部串联
B. 两只并联后与另两只串联
C. 两两串联后再并联
D. 全部并联
【单选题】
用戴维南定理分析电路“入端电阻”时，应将内部的电流源___处理。
【单选题】
任何一个含源二端网络都可以用一个适当的理想电压源与一电阻___来代替。
A. 串联
B. 并联
C. 串联或并联
D. 随意联接
【单选题】
用交流电流表测得交流电流10A，则电路中电流的最大值为___。
A. 10A
B. 14.1A
C. 20A
D. 70.7A
【单选题】
如右图所示电路中，已知各支路的电流I1=I2=10A， 则电路的总电流I为___。
A. 20A
B. 0 A
C. 14.1A
D. 50A
【单选题】
1杂质半导体中多数载流子的浓度取决于___
【单选题】
2在电场作用下，空穴与自由电子运动形成的电流方向___
推荐试题
【单选题】
How can you mitigate attacks in which the attacker attaches more than one vLan tag to a packet？___
A. Assign an access VLAN to every active port on the switch
B. Disable Ether Channel on the switch
C. Explicitly identity each VLAN allowed across the trunk
D.
E. nable transparent VTP on the switch
【单选题】
Which technology can you implement to centrally mitigate potential threats when users on your network download files that might be malicious？___
A. Enable file-reputation services to inspect all files that traverse the company network and block files with low reputation scores
B. Verify that the compa ny IpS blocks all known malicious website
C. Verity that antivirus software is installed and up to date for all users on your network
D. Implement URL filtering on the perimeter firewall
【单选题】
What is the most common implementation of PaT in a standard networked environment？___
A. configuring multiple external hosts to join the self zo ne and to communicate with one another
B. configuring multiple internal hosts to communicate outside of the network using the outside interface IP address
C. configuring multiple internal hosts to communicate outside of the network by using the inside interface IP address
D. configuring an any any rule to enable external hosts to communicate inside the network
【单选题】
Which component of a bYod architecture provides aAa services for endpoint access ?___
A. Integrated Services Router
B. access point
C. ASA
D. Identity Services
E. ngine
【单选题】
You are configuring a NAT rule on a Cisco ASA ,Which description of a mapped interface is true?___
A. It is mandatory for all firewall modes
B. It is optional in routed mode
C. It is optional in transparent mode
D. It is mandatory for ide ntity NAT only
【单选题】
Which description of the use of a private key is true ？___
A. The sender signs a message using the receivers private key
B. The sender signs a message using their private key
C. The sender encrypts a message using the receivers private key
D. The receiver decrypts a n15ssage using the sender's private key
【单选题】
Which mechanism does the FireAMP Connector use to avoid conflicts with other security applications such as antivirus products ?___
A. Virtualization
B. Containers
C. Sandboxing
D.
E. xclusions
【单选题】
Which network to pology de scribes multiple LANS in a gec? ___
A. SOHO
B. MAN
C. pan
D. CAN
【单选题】
Which statement represents a difference between an access list on an aSa versus an access list on a router？___
A. The asa does not support number access lists
B. The aSa does not support standard access list
C. The asa does not ever use a wildcard mask
D. The asa does not support extended access lists
【单选题】
Which command do you enter to verify the status and settings of an iKE Phase 1 tunnel？___
A. show crypto ipsec as output
B. show crypto isakmp
C. show crypto isakmp policy
D. show crypto ipsec transform
【单选题】
Which feature can help a router or switch maintain packet forwarding and protocol states despite an attack or heavy traffic load on the router or switch？___
A. service Policy
B. Control Plane Policing
C. Policy Map
D. Cisco
E. xpress
F. orwarding
【单选题】
Which STP feature can prevent an attacker from becoming the root bridge by immediately shutting down the interface when it receives a BPDU？___
A. root guard
B. Port Fast
C. BPDU guard
D. BPDU filtering
【单选题】
Which technology can best protect data at rest on a user system？___
A. full-disk encryption
B. IPsec tunnel
C. router ACL
D. network IPS
【多选题】
Which two primary security concerns can you mitigate with a BYOD solution ？___
A. schedule for patching the device
B. securing access to a trusted corporate network
C. compliance with applicable policies
D. connections to public Wi-Fi networks
E. device tagging and invento
【多选题】
choose five___
A. MD5————————inserure
B. DES————————insercure
C. SDES———————legacy
D. SHA-1———————legacy
E. HMAC-MD5—————legacy
【多选题】
Which two characteristics of symmetric encryption are true？___
A. It uses digital certificates
B. It requires more resources than asymmetric ancryption
C. It uses the same key to enctypt and decrupt traffic
D. It uses a public key and a pricate key to encrypt and decrypt traffic.
E. It is faster than asymmetric encryption
【多选题】
which two characteristics of PVLAN are true？___
A. Promiscuous porta can communicate with PVLAN ports.
B. Isolated ports cannot communicate with other ports on the same VLAN
C. Community ports have to be a part of the trunk.
D. They require VTP to be enabled in server mode
E. PVLAN ports can be configured as Ether Channel ports
【多选题】
What are two options for running Cisco SDM?___
A. Running SDM from a mobile device
B. Running SDM from within CiscoWorks
C. Running SDM from a router's flash
D. Running SDM from the Cisco web porta
E. Running SDM from a PC
【多选题】
Which two options are the primary deployment modeles for mobile device management？___
A. multisite
B. cloud-based
C. on premises
D. hybrid cloud basedo
E. single site
【多选题】
Drag the recommendation on the left to the Cryptographic algorithms on the right， Options will be used more than once.___
A. Avoid——————————————DES，MD5
B. Legacy——————————————SDES，SHA1，HMAC-MD5
【多选题】
Which two are valid types of vLans using PVLANS ?___
A. Community VLAN
B. Backup VLAN
C. Secondary VLAN
D. Isolated VLAN
E. Isolated VLAN
【多选题】
Which two commands are used to implement Resilient lOS Configuration ___
A. Secure boot-config
B. copy running-config tftp
C. copy flash:ios bin tftp
D. copy running-config startup-config
E. secure boot-image
【多选题】
Which two types of firewalls work at layer 4 and above ？___
A. Stateful inspection
B. Network Address Translation
C. Circuit-Level gateway
D. Static packet filter
E. Application Level firewall
【多选题】
Which two default settings for port security are true ？___
A. Violation is Protect
B. Violation is Restrict
C. Violation is Shutdown
D. Maximum number of MAC addresses is 2
E. Maximum number of MAC addresses is 1
【多选题】
Which two are characteristics of RADIUS？___
A. Uses UDP ports 1812 /1813
B. Uses TCP port 49
C. Uses UDP port 49
D.
E. ncrypts only the password between user and server
【多选题】
When setting up a site-to-site VPN with PSK authentication on a Cisco router， which two elements must be configured under crypto map？___
A. pfs
B. nat
C. reverse route
D. peer
E. transform-set
【多选题】
When using the Adaptive Security Device Manager（ASDM), which two options are available to add a new root certificate？___
A. Install from SFTP server
B. Usehttps
C. Install from a file
D. Use LDAP
E. Use SCEP
【多选题】
Which two SNMPv3 services support its capabilities as a secure networ k manage protocol？ ___
A. access control
B. the shared secret key
C. authentication
D. authorization
E. accounting
【多选题】
Which two statements about routed firewall mode are true ？___
A. The firewall acts as a routed hop in the network
B. This mode conceals the presence of the firewall
C. The firewall requires a unique iP address for each interface
D. This mode allows the firewall to be added to an existing networ k with minimal additional configuration By default， this mode permits most traffic to pass throug
【多选题】
Which two statements describe DHCP spoofing attacks？___
A. They are used to perform man-in- the-middle attacks
B. They can access most network devices
C. They can modify the flow of traffic in transit. LNGKAIG
D. They protect the identity of ti attacker by masking the DHCP address
E. They can physically modify the network gateway
【多选题】
Which two types of VLANs using PVLANs are valid？___
A. isolated
B. promiscuous
C. backup
D. secondary
E. community
【多选题】
What are two limitations of the self-zone policies on a zone-based firewall？___
A. They are unable to block Https traffic
B. They restrict SNMP traffic.
C. They are unable to support Https traffic
D. They are unable to implement application inspection
E. They are unable to perform rate limiting
【多选题】
Which two descriptions of TACACS+ are true？ ___
A. The TACACS+ header is unencrypted
B. It combines a uthentication and authorization
C. It uses TCP as its transport protocol
D. Only the password is encrypted.
E. It uses UDP as its transport protocol.
【多选题】
Which two actions does an IPS perform？ ___
A. it spans the traffic
B. it reflects the traffic back to the sender
C. it encrypts the traffic
D. it terminates the user session or connection of the attacker
E. it reconfigures a device to block the traffic
【多选题】
In which form of fraud does an attacker try to learn information such as login credenti account information by ma squerading as a reputable entity or person in email， IM or communication channels ?___
A. phishing
B. Smurfit
C. Hacking
D. Identity Spoofing
【多选题】
Which two ESA services are available for incoming and outgoing mails ？___
A. anti-DoS
B. reputation filter
C. antispam
D. content filter
E. DLP
【多选题】
What are two reasons to recommend SNMPv 3 over SNMPv2？___
A. SNMPv3 is secure because you can configure authe ntication and privacy
B. SNMPv3 is insecure because it send in formation in clear text
C. SNMPv2 is insecure because it send information in clear text
D. SNMPv3 is a Cisco proprietary protocol
E. SNMPv2 is secure because you can configure authentication and privacy
【多选题】
Which two actions can a zone- based firewall apply to a packet as it transits a zone pair？___
A. drop
B. inspect
C. queue
D. quarantine
【单选题】
Which security principle has been violated if data is altered in an unauthorized manner？___
A. accountability
B. confidentiality
C. availability
D. integrity
【单选题】
Which IKE Phase 1 parameter can you use to require the site-to-site VPN to use a pre-shared ？___
A. encryption
B. authentication
C. group
